I prefer to c-bet on the larger side for 3 main reasons.
1 - I play micro SNG and MTT and in most raised hands I face multiple callers and a larger c-bet size helps thin the field of those players who will chase their draws if there is a caller ahead of them.
2 - Again, at the mocro's I see more fit/fold, and call off the stack with TPTK type players. If they fit, and I feel I am stronger (such as KK vs AQ on a Q high board) a larger size makes it easier to get in more money on the turn/river. If they don't they fold, and I take an easy pot.
3 - Lastly, at micro's there are more players willing to stack off with a moderately wide range. I frequently see hands like A10 off and 66 going to showdown after a 4 5 10 flop. Many players will call or shove over a large c-bet with AK on a low board, or call you with Ax where x is some raggy pair on a mid board. By c-betting large against this type of player, they may think you missed and will come over the top with A strong hands and low pp's.
I feel in tourney play one should play for stacks as often as possible. This is not to say play many big pots with alot of hands. I play very tight/positional in MTT's and slightly looser in SNG's. But when I do play a hand, I try to size my post flop bets to win the entire stack if I feel I am strong enough to do so.
Though, I must admit I tend to try it almost every hand I enter and thereofre it often blows up in my face. This is a leak for me. Not c-beting large per-se, but always c- betting on the large side. Does always leaning to the large (usually 2/3 size) make me look like I'm playing scared?