calling raises from the blinds

[dnord]

I've been trying to tighten up the gap between my VPIP and PFR numbers, and one of the things I used to do absolutely habitually was to call raises in the blinds with a large range of hands (all PP's up to QQ, SC 87+, AJ+, KQ, suited aces). AA, KK, and AK were usually exceptions, but I was calling with those about 1/3 of the time for deception.

But after reading a lot of the stickies, I starting thinking about c-betting being our bread and butter here in uNL, and how calling wasn't affording me the opportunity to do much more than donk-bet if I hit or c/f if I missed (probably profitable in uNL, but we can do better).

I've started 3-betting the better half of those hands and folding the rest. I'm running at 19/17 or so, seeing pre-flop folds a ton (particularly if I'm 3-betting a BTN or CO raiser), and the c-bets (even out of position) are picking up nice pots a good chunk of the time.

I've read some advice, though, that makes me think I ought to be mixing in some calls - mainly with speculative hands (that I'm assuming we'll pot flop if we hit a monster or a nice draw). As soon as I start doing this, though, I slide to a comfy 28/14, start finding myself in questionable spots, etc. It feels like I'm continually rethinking my stance on this: against a 25/20 UTG raiser, I'll be pretty sure I can fold him out with a 3-bet from the SB, but if I'm called, I'm sure I'm behind and shut down with my TT or whiffed AQ or whatever. But against a fishier 50/10 type, I feel like I shouldn't be isolating with my drawy hands - I'll be out of position, probably bluffing into players that can't / won't fold.

So what do you consider when you're facing raises in the blinds? When might you just call? Is it a constantly evolving mix of hand strength / opponent reads or are there some solid rules of thumb to keep in mind while multi-tabling?