Thought about this a little more…

You could stick it all in after his flop raise. That would keep his range wider and probably make it profitable.

Thinking about what hands he could have on that flop after he check raises you. He was getting close to 8/1 preflop on his call so he could justifiably be playing any 2 cards. As a side note since the checkraise is so small it looks to me like he’s wanting action and that his hand is strong already, maybe a draw would try and push you off the pot with a bigger raise. I don’t think he has a one pair hand here.

So for me the likely hands are J8,85,T9,76,97,88,55 and most Ax of diamonds. Having run the figures against that range your almost exactly 50% to win on the flop. Maybe we should take some percentage points off to accommodate the bet size indicating a made hand but your still not in seriously bad shape since he still has a lot of potential draws.

When you flat and the 7d hits on the turn you’ve gotta think that improved a lot of his draws which is therefore an awful card for you. Against the range we gave him on the flop your hand now has only 26% to win. You obviously can’t do calculations like this while playing but you should learn to think in these general terms and do this math afterwards, get a feel for how strong some hands are against certain ranges.

For me flatting or shoving the flop are both reasonable options since when you shove there’s still so many draws in his range that call you to get value from. If the board wasn’t so draw heavy, unsuited and unconnected, then shoving is out of the question since the only hands that call you are made hands since there are no draws in his range to get value from.

Once you flat and the 7d comes you have to reevaluate the relative strength of your hand. I think shoving here is spewy since a lot of his draws hit and you only get action from better hands. I like checking back the scary turn card for sure.

maybe the range we gave him should include more pair+flush draws (5x of diamonds) and naked flush draws and give or take a couple of other combos. The general thought process is the main part that will improve your postflop. Sorry for the long-winded post I hope it helps.

After knowing results I have to say I don't see anything wrong with the play or bet sizing up until the turn. The 2x pf and the ~1/2 pot cbet is what everyone preaches…it gives you the chance to get away from the hand without commiting those extra chips. I don't think that sizing necessarily works well at the small stakes I play but in this field it should be effective.