Thanks for all your replies. This is why I posted - I expected views to range from "I"m folding" to "never ever folding" which is exactly what I"ve got.
Easy one first - I"ve adjusted my M for the fact that we"re 6-handed (i.e. M=M*6/10). I read Harrington and have always done this, exc. heads up.
I have to confess I wrapped myself in circles on his reraise. When I said I knew he was a decent player, it was literally only that - he"s not a complete donk. Not a huge amount to go on in this comp, other than noticably opening up since the antes kicked in and we became short handed.
The conclusion I came to, as played, was that he can only be drawing. I haven"t been c-betting often enough (or indeed playing enough hands) for him to be sure he can CR the flop with the overpair, top 2 or even the set.
I took the most popular route on here and shoved. Villain called and showed ad
for one of those "ahead but behind" spots, beating ace high but a slight dog.
FWIW, jd on the turn hence my op being posted early on the same evening
Given my time again I probably still 3-bet pre but maybe for more. Maybe also check-call it down, but think it"s a bit hindsight-led.