kathy, 2 55's on a 29 gallon tank is pretty good. i try to tell everyone to shoot for 6-8 watts per gallon, as this is a nice general area that most corals will fall right into. as far as plugging a 65w bubl into a 55 ballast, you can do it. i didi this with my set up which is custom sea life, and they told me the bubls will fire up exactly the same. good stuff
fishman, i would also throw two 55's on there, or two 65's. this is what i am currently running on my 20, 2 65 watt custom sea life bulbs, but will be upgradign with more pc's very soon!
anyhow, good luck all, and enjoy!
jon