"Do you look at villain's line very often in terms of being value / bluff heavy?"
Yes and no. There are some lines that I think are pretty clearly over/under bluffed and I'll adjust accordingly. Others, especially more rare ones, I'm a little more reluctant to do so. For example, I would be shocked if you have a big enough sample to confidently say that raise preflop, xx flop, xr turn, overbet river BvB is overbluffed, I think that might be the only time I've ever faced that line! In game it felt like a line where there are very few value combos, I have a hand that probably calls sometimes in solver and it's easy to overbluff so I called. In retrospect I'm not sure I like that line of thinking but at 200/500 I've found there's a decent chunk of people who are way overbluffing in spots that people are capped (or perceived to be capped)

Steve Paul I put this hand into wizard because I was curious about the calling range myself. It looks like we want to unblock the 9x / 7x region as that is the bluffing region for the SB and also prefers to call with hearts. I'm a bit surprised still by the calling range. Even TX seems to be over folding quite a bit here. Wizard calling range This is for general 2.5x using 3x open. XX flop. 50% turn stab with 100% XR size. Then I looked at 85% and 150% river sizes. However, we know practice is different than solver land.

I was thinking back to one of Nuno's HU videos where he talked about unblocking Ace high flush draw because it blocks the XC XC XF range. There is something here about unblocking nutted hands in a polarized range. If you think of a heuristic for this spot, let me know! Because I even see T9o folding quite a bit!

In terms of sample size, you are right I don't have a sample size. I try and think of it in terms of how many bets are being put into the pot. I know when 3 bets are put into the pot in a B-B-B line its under bluffed. I would treat X-XR-B in a similar fashion.