I'd raise the flop harder, your raising less than 1/2 the pot and that won't get you the information you need. Would it not be better to force him to define his hand instead of lots of weak little bets that tell you nothing? A pot sized raise on the flop could (possibly) get a fold from JJ / QQ as you have repped AA / KK with your pre-flop re-raise. A big raise would also change calling with overcards from a small mistake into a big mistake.