diff --git a/DESCRIPTION b/DESCRIPTION
index 46c169c..dc5a0b1 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,6 +1,6 @@
 Package: link
 Title: Stream Network Habitat Interpretation (Experimental)
-Version: 0.41.0
+Version: 0.41.1
 Date: 2026-05-27
 Authors@R: c(
     person("Allan", "Irvine", , "airvine@newgraphenvironment.com",
diff --git a/NEWS.md b/NEWS.md
index 2ee4c7d..b3622f9 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,3 +1,7 @@
+# link 0.41.1
+
+`data-raw/study_area_run.sh` gains a `--schema=<persist-schema>` flag for side-by-side bundle compares. Without the flag, behaviour is unchanged (config's YAML `pipeline$schema` default). With the flag, the driver exports `LNK_SCHEMA` so all per-WSG R scripts (`wsg_run_one.R`, `wsg_recompute_one.R`, `study_area_compare.R`) override `cfg$pipeline$schema` at runtime. The propagation works through SSH to cyphers too (each remote shell exports `LNK_SCHEMA` before its WSG loop). Use case: `--config=default --schema=fresh_default` lets a default-config run land in `fresh_default` without clobbering an earlier `--config=bcfishpass` baseline in `fresh`. Empty `--schema=` value errors loudly rather than silently falling through to the YAML default. Live-validated on ADMS (2.2 min, 11 species habitat tables landed in `fresh_default`, `fresh` untouched).
+
 # link 0.41.0
 
 New exported function `lnk_wsg_resolve()` — the bundle-aware "what WSGs should we model?" resolver ([#207](https://github.com/NewGraphEnvironment/link/issues/207)). Composes the FWA drainage closure (now a fresh primitive: `fresh::frs_wsg_drainage()`, [NewGraphEnvironment/fresh#211](https://github.com/NewGraphEnvironment/fresh/pull/212) / fresh v0.32.0) with the bundle's `wsg_species_presence` filter (link#157). Three call patterns dispatched by `(wsgs, expand)`: province mode (`wsgs = NULL` → all bundle-species WSGs, sorted alphabetically), closure mode (`wsgs = c(...), expand = TRUE` → focal + drainage closure, DS-first preserved), strict mode (`wsgs = c(...), expand = FALSE` → species-filter input verbatim). Validation mirrors `lnk_pipeline_species`; closure mode opens its own DB conn via `lnk_db_conn()` with `on.exit` cleanup; closure + strict modes emit `message()` listing any species-less WSGs dropped from the result (parity with the previous inline diagnostic). New `@family wsg` — pre-stages a `lnk_wsg_*` family for follow-on topology helpers (e.g. cross-host DS-first bucketing).
diff --git a/data-raw/study_area_compare.R b/data-raw/study_area_compare.R
index c3fa52e..03e4112 100755
--- a/data-raw/study_area_compare.R
+++ b/data-raw/study_area_compare.R
@@ -28,6 +28,11 @@ suppressPackageStartupMessages({
 source("data-raw/wsg_compare.R")
 
 cfg <- lnk_config(config)
+# LNK_SCHEMA env var (set by study_area_run.sh --schema=) overrides the
+# config's YAML default persist schema. Compare must read from the schema
+# the run/recompute wrote to.
+.lnk_schema_env <- Sys.getenv("LNK_SCHEMA")
+if (nzchar(.lnk_schema_env)) cfg$pipeline$schema <- .lnk_schema_env
 
 rows <- list()
 for (w in wsgs) {
diff --git a/data-raw/study_area_run.sh b/data-raw/study_area_run.sh
index 201d785..e96f371 100755
--- a/data-raw/study_area_run.sh
+++ b/data-raw/study_area_run.sh
@@ -24,7 +24,7 @@
 #     --focal=<dispatcher focal csv> \
 #     --focal=<cy1 focal csv> \
 #     --focal=<cy2 focal csv> \
-#     [--config=bcfishpass] [--keep-cyphers]
+#     [--config=bcfishpass] [--schema=<persist-schema>] [--keep-cyphers]
 #
 # The number of --focal flags MUST equal 1 (dispatcher) + N cyphers, in
 # order: first --focal -> dispatcher, the rest -> cyphers in --cy-workspaces
@@ -38,12 +38,15 @@ set -euo pipefail
 # --- args ---
 CY_WS=""
 CONFIG="bcfishpass"
+SCHEMA_OVERRIDE=""
 KEEP_CYPHERS=0
 FOCAL_ARR=()
 for arg in "$@"; do
   case "$arg" in
     --cy-workspaces=*) CY_WS="${arg#--cy-workspaces=}" ;;
     --config=*)        CONFIG="${arg#--config=}" ;;
+    --schema=*)        SCHEMA_OVERRIDE="${arg#--schema=}"
+                       [ -n "$SCHEMA_OVERRIDE" ] || { echo "FATAL: --schema= requires a non-empty value" >&2; exit 1; } ;;
     --focal=*)         FOCAL_ARR+=("${arg#--focal=}") ;;
     --keep-cyphers)    KEEP_CYPHERS=1 ;;
     *) echo "unknown arg: $arg" >&2; exit 1 ;;
@@ -73,10 +76,18 @@ CYPHER_TF="$HOME/Projects/repo/rtj/env/do/dev/cypher"
 # cypher_prep does `git fetch origin && git reset --hard origin/$BRANCH`.
 LINK_BRANCH="$(git -C "$REPO_ROOT" branch --show-current)"
 
-# Resolve persist schema (don't hardcode "fresh").
-SCHEMA=$(cd "$REPO_ROOT" && Rscript -e \
-  'cat(link::lnk_config(commandArgs(TRUE)[1])$pipeline$schema)' "$CONFIG" 2>/dev/null || true)
+# Resolve persist schema: --schema= overrides the config's YAML default
+# (e.g. for side-by-side bundle compares: --config=default --schema=fresh_default
+# keeps the bcfp-config run intact in `fresh`). All R scripts read LNK_SCHEMA
+# below and override `cfg$pipeline$schema` if it is non-empty.
+if [ -n "$SCHEMA_OVERRIDE" ]; then
+  SCHEMA="$SCHEMA_OVERRIDE"
+else
+  SCHEMA=$(cd "$REPO_ROOT" && Rscript -e \
+    'cat(link::lnk_config(commandArgs(TRUE)[1])$pipeline$schema)' "$CONFIG" 2>/dev/null || true)
+fi
 [ -n "$SCHEMA" ] || { echo "FATAL: could not resolve persist schema for --config=$CONFIG"; exit 1; }
+export LNK_SCHEMA="$SCHEMA"
 
 echo "=== study_area_run $TS ==="
 echo "  config:       $CONFIG"
@@ -208,7 +219,7 @@ LOCAL_PID=$!
 declare -A CY_PID
 for WS in "${CY_WS_ARR[@]}"; do
   IP="${CY_IP[$WS]}"; B_SPACE=$(echo "${CY_BUCKET[$WS]}" | tr ',' ' ')
-  ssh "cypher@$IP" "cd ~/Projects/repo/link && for w in $B_SPACE; do Rscript data-raw/wsg_run_one.R \$w '$CONFIG' || echo \"[WARN] cy WSG \$w failed\"; done" \
+  ssh "cypher@$IP" "cd ~/Projects/repo/link && export LNK_SCHEMA='$SCHEMA' && for w in $B_SPACE; do Rscript data-raw/wsg_run_one.R \$w '$CONFIG' || echo \"[WARN] cy WSG \$w failed\"; done" \
     > "$LOG_DIR/${TS}_run_$WS.log" 2>&1 &
   CY_PID[$WS]=$!
 done
diff --git a/data-raw/wsg_recompute_one.R b/data-raw/wsg_recompute_one.R
index d8d8f2f..e42cbf7 100644
--- a/data-raw/wsg_recompute_one.R
+++ b/data-raw/wsg_recompute_one.R
@@ -43,6 +43,11 @@ DBI::dbExecute(conn, "SET statement_timeout = '600000'")  # 10 min / statement
 DBI::dbExecute(conn, "SET lock_timeout = '60000'")        # 1 min on lock waits
 
 cfg    <- lnk_config(config)
+# LNK_SCHEMA env var (set by study_area_run.sh --schema=) overrides the
+# config's YAML default persist schema. Recompute must match the schema
+# used by the run/consolidate phases.
+.lnk_schema_env <- Sys.getenv("LNK_SCHEMA")
+if (nzchar(.lnk_schema_env)) cfg$pipeline$schema <- .lnk_schema_env
 loaded <- lnk_load_overrides(cfg)
 
 active <- lnk_pipeline_species(cfg, loaded, wsg)
diff --git a/data-raw/wsg_run_one.R b/data-raw/wsg_run_one.R
index 0adc8a1..daefa50 100755
--- a/data-raw/wsg_run_one.R
+++ b/data-raw/wsg_run_one.R
@@ -34,6 +34,12 @@ conn <- lnk_db_conn(dbname = "fwapg", host = "localhost", port = 5432L,
 on.exit(try(DBI::dbDisconnect(conn), silent = TRUE), add = TRUE)
 
 cfg    <- lnk_config(config)
+# LNK_SCHEMA env var (set by study_area_run.sh --schema=) overrides the
+# config's YAML default persist schema — used for side-by-side bundle
+# compares so e.g. `--config=default --schema=fresh_default` doesn't
+# clobber an earlier `--config=bcfishpass` run sitting in `fresh`.
+.lnk_schema_env <- Sys.getenv("LNK_SCHEMA")
+if (nzchar(.lnk_schema_env)) cfg$pipeline$schema <- .lnk_schema_env
 loaded <- lnk_load_overrides(cfg)
 
 # Defensive skip (link#157): a WSG with no bundle-species presence can't be