Reraising - what's a good size?

Hello pokergods,
I wonder what you experts consider to be a standard (or good) size for a reraise when you have position on the original raiser?

Preflop – if there is an opening-raise (R1) of 4*BB from MP, no calls and you reraise with >JJ/AK in LP. How much of a raise would you put in?

Suppose you know this particular raiser will open in MP with the following hands: 99/AQ/AJs (72 hands, of which there are 36 pairs 99+).

2.5*R1 would lay about 1:2.6 pot-odds for the raiser who is OOP.
A miniraise of 2*R1 yields about 1:3.4.
What's your move?

Also related situation: you have limped in and taken a cheap flop in LP with 44 behind 2 limpers, SB completes (Potsize: 5BB). Flop comes A94, with 94 of same suit. Both blinds and the first limper check, and there is a pot-sized bet from the second limper. You read the guy for either AQ-AT or Ax-suited on a strong nut-flush draw with top pair. He may also be on a steal.
Action to you. You face a bet of 5BB (current potsize = 10BB).

How much do you reraise? And if you say pot-sized, exactly what does that mean?

Grateful for suggestions!
/
roy3

Preflop if you are in position with a hand better than JJ or A/K (that what you meant by the > sign right?) I would re-raise as much as i think the guy would call when the range of hands you can put him on includes 99-AQ (hands you dominate, all of them), then push/bet out the flop to a raggy board or slowplay if you make a big hand (set).

In the situation where you flop the set of 4's, re raise enough to give him bad pot odds for the flush draw if thats what he's on. If you don't put him on AA/99, you're ahead here. Give him bad odds and play the turn/river based on what falls and how he acts. You're in position, so if the flush card hits, you can get out of there. As long as you give him bad odds to make his flush on the flop, its +EV.

this again....

it depends on the player. I read a "good" player for KK yesterday when I had AA, so I bet 2 times the pot on the flop, and he pushed. Exactly what I wanted him to do

Against a fish, I'd give him odds to call, hell i might not even raise from SB if i think BB is weak (if table folded).

generally, a 2-3 reraise is good enough to keep a weaker player in the hand. Maybe more if he's loose. Reads are so important for NL.