I was playing a nine-handed 1/3 cash game with the table playing fairly deep all the way around ($300-$500 each player) and I ended-up holding pocket aces on the button. Before I acted pre-flop, there were five limpers followed by a cutoff raise to only $7 (odd since no less than $12 was very effective in thinning the field without limpers, however, this type of small/min raising after multiple limpers was being done by a couple of players so it wasn't completely out of nowhere...such a raise had virtually zero effect and would be called by all limpers...I found $15 + $3 per limper to be consistently effective in thinning the field to one or two opponents). Normally, I would re-raise three times the prior raise amount, however, with such a small raise and so much money in the pot from the limpers, how should I size my re-raise?