Just some open thoughts on a common spot...

SB: $442 (110.5 bb)
BB: $454.68 (113.7 bb)
Hero (UTG): $400 (100 bb)
MP: $400 (100 bb)
CO: $505.50 (126.4 bb)
BTN: $400 (100 bb)

Preflop: Hero is UTG with X X
Hero raises to $12, MP folds, CO calls $12, BTN raises to $44, 2 folds, Hero ?????

Assume villain is a competent reg and CO is a weaker player/fish. What is your guys' typical 4betting range in this spot? I would think AA-QQ and AK are easy 4bet/calls. This makes 34 value combos so how many bluff combos would be enough to balance? KQ seems like the best combo to bluff with as well.

Lastly, how does your range change (if it does at all) if CO is a competent reg?