Not as simple of a question to answer. My best sizing would depend on several factors. Stack size and pot size. Who I am against and how I think they will react. What I really have vs what I think they have. The truth is we need to bet not a set size but bet for the situation. Don't worry about sizes but look at situations more.
Example from a recent game I played. Tight player raised and I called in the SB with pocket 3's. The pot was pot was 1300. Flop was 2 4 8 rainbow. I checked and they bet 1500. Knowing this player and how passive they were I was certain I was dead as my set missed. The problem with the bet is what would I call them with? I would have raised pre any big hand so I dont have them. There no flush draws and the only straight draws are A3, A5, 56,. 35, 76, 75. Only open ender is the 35 and i am not calling a raise there. So we have gut shots. I could have an 8 here but my kicker is pretty sad if i do. So what are they trying to get value from here on me? All the big bet does is get my junk to fold. See the problem here? On this flop is I have a 8 i can and will call a reasonable bet. Pocket 9's I would as well. What else would I call? This is what you would be better thinking about and not just a bet size. Once you figure out what they could have and what you want to awhile then you can pick a size.
OH so what happened in that hand, I folded and they showed pocket kings. Were they getting paid on this hand no, but again if i called with say 78 they lost a ton of value from me.