Well, you described the CO as a tight player who play horrible postflop, and tried to bluff a CS. This to me would indicate a willingness to make mistakes on pushes. He's probably coming in whether we check or bet in this spot with a big diamond, so I'm not worried about him. The button was described as a CS fish who is also bad in so many different ways. I think he would see a pot that big and come along as well if he saw two people in front of him put alot of money in. I don't feel either of them has a flush. I'm not too worried about the PFRer having a flush, and the button is such a fish that the variety of hands he could have here are large.
When you checked, and the CO pushed(which was probably bound to happen since you did say he played horrible postflop, a good reason not to suspect a flush), you then have to worry about the button. But I don't understand why you think the fish has a flush here very often. Fish also like to call w/ Jx, two pair, a flush draw and straight draw on the turn...or sometimes just a whim and a prayer(it's as if sometimes they aren't even looking at the board).
But if the button has something horrible like TT, 99, J5, KJ, T9 and all sorts of other hands with one diamond and that last diamond hits...I'm feeling bad about not getting my money in ahead when I could have. This was my though process for the turn after you checked and the CO pushes. I feel I am ahead here, andI think giving the button a chance to catch here without making him pay for it is not the right move.
Plus the pot is $330 on the river if I just call and button calls. Button has $90 left and it's going to be pretty hard to get away from this hand here no matter what falls, even though I can't imagine you winning if a diamond hits.
All right, I'm ready. I want to know why my thinking is wrong. I'm bracing myself...
I still have no respect for the people you are playing obviously. Your description of there ineptitude was nicely phrased.