I think the Whisper Power filter is going to be quite undersized for a high light co2 injected 29 gallon. What would be ideal, would be to run 2 cannisters on your 55. You could start 1 of them on the 29, then you would have a cycled filter when you moved over to the 55.
That might not be a bad idea. I am strapped for cash atm but I think I may ask my gf for aquarium stuff for our anniversary in october so that would get it started :-p
Also I was just thinking... I can get the HOB to start (since I already have it) and cycle the tank. Then get 2-3 otto's and a couple snails to keep it going and add the canister filter and get that seeded then eventualy remove the hob to try and convince my g/f on a 3rd tank :-P
This is what I have now for my co2 setup...
Milwaukee Regulator with bubble counter
5# CO2 Aluminum Tank
And I am leaning towards a Rex Riggs Reactor
(easy to build and inexpensive to make)