-Opens very light UTG (though ~somewhat nutty A854ns)
-May check turn in a 3bet pot with topset+nFD to c/rai versus bet, so watch out for check/potting
-Have pot-donked T2P+Flushdraw in a big 3way 3bet pot. Sizing tell? (probably not folding with those stacksizes)

He plays 40/30 over 109 hands, though most of those hands were 6handed with 2 pretty big fish at the table, so that might skew things in any given direction. He seems agro, and my gutfeeling tells me he is probably prone to make aggression-mistakes playing deeper than 100ish bb stacksizes. He is also 3betting 15%, though only a small hand-sample. But that should remove alot of AKQx hands from his flatting-range, I would assume.

I'm playing much tighter, in the 25/18 area.

I just won a pot from him, where he donk-betted bottom-pair + low flushdraw heads up versus me. I called the flop with topset (we were deep) with the plan to raise or bet good turns, hoping the deepness would/could make him make some mistakes. The board got ugly (4cards to a straight) and he bet river into me (after turn went check/check) and I called with the split-straight. He had air, and I won a medium sized pot.

In retrospect, I'm not sure this hand is strong enough to stack off 200bbish deep, with these reads and the slight gutfeel / hope that him seeing me slowplaying set would make him think I'm bluffing here.

Thoughts on this part in particular?

I'm kind of lost here. Not to keen on bet/comitting, and not to keen on giving up value versus worse hands that might call. With the ammount of reads I don't feel competent enough to know whether or not I can bet/call for value/protection, or if I have to bet/fold.

Are we checking behind, with plan to valuebet(/fold) flushes. Valuebet house, and bluff-catch alot of rivers, or are we bet/shoving / bet/folding?