I try not to vary my bets based on what I have; rather, I'll bet based on the board and opponents.
For example, if I'm in opening the betting in late position, my bet with AA will be the same as with 87s.
If I have a hand post-flop, I want to protect against draws, so bet according to the board. Eg: 2 diamonds and T9 on the flop, I am betting more than I would on a board with fewer drawing opportunities.
I am betting the same way if I am bluffing or semi-bluffing. I might want a total bluff to look like a semi-bluff, so will bet small on a drawy board, so if a scare card hits, I can represent that I made my monster hand.
This all can go out the window based on opponents -- if you can narrow their range of action, you might change the way you bet against them. This comes into play on those river bets -- a small (1/3 pot) bet may induce a weak call, but it also makes it look like you WANT them to call, so may get a fold. A larger bet (more than the pot) might make you look desperate to induce a fold, but if you've done that already and shown a big hand, you may get some calls on those, too.
Sorry I didn't answer the questions specifically, but I hope this at least gives you something to think about, as ultimately these decisions are up to you!
Good luck and enjoy your games!