Defending our Range

Basic pot odds - in a range vs. range situation when one player bets he's giving himself odds to win the pot. If his opponent folds more than X % of his range in that spot where X = Risk /(Risk + Reward) then he can bet his entire range and make an immediate profit. Suppose we're the other player, we obv cannot allow villain to bet his entire range profitably so we must not fold at least Y % where Y = 1 - X. Right sorry to mash all that stuff out again it's pretty fundamental. But I think recently in my play I'd been neglecting the second part. My database shows that in HU pots I've been folding to c-bets around 43% of the time and I think that this is too high. I'm being exploited on the flop so I need to find a solution to this. One is to play back more, another is to tighten up. If we call with less speculative hands then we'll be able to defend our range much more easily since we'll have good hands more often. Trying to keep the betting lead the vast majority of pots I play in is allowing me to take advantage of people who are not defending their range enough while I'm not making the same mistake. The downside is that I'm consequently a gigantic humongous NIT.
Another thing I've noticed in my database is that set mining with the following hands {22-66} is losing me money in heads-up pots, especially out of the blinds. When I filter the same hands in multi-way pots they do just fine. So the moral? - overcalling to set mine in a multi-way pot is fine but calling heads-up is not. Of course turning these hands into bluffs some of the time may compensate for this but I'm not good enough to find these spots just yet so it's probably better for me to cut them out of my HU calling range altogether.

EDIT:
I've just looked at some more stats in my database. I filtered for flops where I put out a raise. Three figures stand out :
1/ W$WSF - the amount of time I won money when I saw a flop is massive at around 75%
2/ WTSD - the amount of time I went to showdown is around 35%
3/ W$SD - the amount of time I won at showdown is around 60%
The conclusion to be drawn here is that I have been value betting much more often in these spots than I've been bluffing. I touched on this before where I spoke about playing too fit or fold on the flop. Now this is fine at these limits where it's clear I'm being paid off when I do raise here entirely for value. However, I think that I'm missing out on some no showdown winnings so I need to do some work to find some spots where I can put out a bluff raise or two more. The goal is to sacrifice some showdown winnings (since we've got plenty to work with) in order to hopefully win more no showdown winnings. This should also allow us to get paid off more often when we have the goods. GL