My crash problem has been resolved! (I think)
Well the good news is on my initial tests, it appears I no longer have the crash issues I once had with data assist. The bad news is, it's very tough to nail down what did the trick, as I just got a brand new imac up and running with the fastest processor available, installed a fresh copy of DW 2017 and all my webassist extensions. I'll be putting it to the test with more complicated scenarios later this week but it looks good so far.