I always forget about wa handles when I'm going off about spalted woods. I can see how spalted stuff would work a lot better with a wa handle than westerns. It's all those curves and metal bits making it a pain in the ass to deal with on western handles versus the flats of a wa handle. Then again some spalted woods (like the awesome HI Signature & Norfolk Pine) that you supply never cause me problems.
Most importantly though is the stabilizer source used to treat the wood - that's key to the wood being great or crap.