I completely agree Turtle420.

But i think shorter pots are valid. You can use large pots but short.

Other way in gain some inch is using slim CFLs. Try to get type L CFLs. They are best efficients CFLs, and only gets 1" in height. 3 of 55w will give you far larger yields than 6 24w CFL. In fact, with 2 of 55w you will get the same light than with your smaller CFLs. They last longer, too. And its ballast can be placed out the cabinet, reducing the heat to manage (always a problem in very small cabs).