Allow the dish to also cut in to the stem part

[mvaneijgen]

To be honest I'm trying to make a weird shape key, but I just can't seem the make the top of the key thick enough to have the dish be cut out of it. The stem part always pokes through. Would be nice to have the dish shape also cut the top of the stem part.

This is a 1.5 DSA type key with a spherical dish and a tilt

https://gist.github.com/mvaneijgen/e1e10fe3d27e8edf323f5317c74f083c