$600 effective stacks.
CO is a fish and calls a lot.

Pre-flop: (5 players) Hero is SB with
UTG calls, CO calls, Button folds, Hero raises to $30, BB folds, UTG calls, CO calls.

Flop: ($93, 3 players)
Hero bets $75, UTG folds, CO calls.

Turn: ($243, 2 players)
Hero checks, CO bets $65.05, Hero raises all-in $525.44

Hmmmm. I think he'd have to be really really bad to call without an 8. I kinda want to just bet the turn and hope to induce a bluff and grit my teeth and call it, buuut you said he's fishy and not maniacal sooooooooo I dunno.

Your CR all-in won't fold any better hands than yours. And it will fold a whole lot of worse hands than yours. So, maybe I'm missing something, but I don't see the point.

Seems like this way loses the max against the hands that are beating you, and wins the minimum against most of the hands that you beat.

I suppose it kills his odds if he happens to be on the FD... Or he could have 2 pair and be willing to go to the wall with it.

What did you put him on? Or does it not matter, because he's a donk who loves to call?

I really think a call is far superior here. You're getting great odds, and as the others say you'll (probably) fold most of the hands that you beat with that CR. I'd suggest flat calling and then betting the river (and folding to a big raise if the board is unpaired).