After a month of trial and error I might have stumbled across a solution that finally solves the OSX instability issues that lead to unexpected lockups or crashes (often unrecoverable necessitating a hard power).
So far it seems to be stable. I successfully ran 3 clients for about 4 hours without incident. Believe it or not, the solution appears to be ridiculously simple: You can’t run any window larger than 1600x900. The graphics settings have zero bearing on stability (other than frame rate).
Two things I also did that may or may not have contributed in a minor fashion was to set Wine to the latest CCP dev version and fix the graphics memory at 3072MB (4096MB is the max EVE seems able to use and when you run auto detect I have a feeling it’s assigning more than is available).