HOWEVER!!! After messing more with the Rect Support, I realized that its shadow support was its own independent implementation! I had thought it was simply a compatibility layer of some sort. It is working exactly as I was looking for! Thank you for the help there! (Also also, I have found an out of index bug within UpdateMaskingOnAllSubmeshes() that I'm hoping to have a writeup on soon... so apologies in advance for picking on you XD).
