Haven't played at 50NL in a long time... do most players fold to pre-flop raises and those who don't usually fold to c-bets? That's how most of 200NL full-ring plays and I raise a lot pre-flop to take advantage. If 50NL is looser pre- and post-flop (as I imagine it is) I don't think there's much value in raising in 1 & 2. I always call in 3. You have a chance to stack a tight player, or outplay him if he don't hit the flop. It's an easier call if you have the right post-flop reads on him (always c-bets, doesn't second barrel, stacks off with KK+ no matter what, won't felt a one pair hand, etc.). In 4 I like a call b/c you're probably close to even with his range, it's a small raise and you have position.