Where described as "big scopes" & "potato chip" mirrors, what aperture *range* are you talking about? Assuming *decently* designed mirror cells & overall scope structures, where (aperture-wise) do these issues first BEGIN to come into play, & where do they become more significant, or problematic? From what you've already stated, i think i can safely infer we're talking beyond 8" mirrors... but HOW far? I understand these are necessarily your opinions on the matter, but i respect your experience there- as well as others who are much more familiar than i with this species of beast!
... I have to say that there are few instances where the trouble messing with the big scopes is really worth the effort, and truth be known, I'm willing to wager there is a tendency to get optical trains that as a rule are inferior to smaller aps. When the weight of just the glass alone warps the mirror into a potato chip, I think I'd rather put my efforts into something else that's more consistent and with higher quality.