I'm only checking Hand 4 if I have reads to either confidently call or fold turns. otherwise a 27/7 is going to have so much crap that isn't pairs and if he's going to lead the turn with it any decent % and you're going to fold it doesn't matter if only worse is calling on the flop because your c bet's still going to be more profitable vs his range. If he's tighter preflop, checking's better. Basically with all else aside your c bet will show an immediate prpfit and checking will lead to making mistakes or an inferior play without decent reads.