I'll bet that the Frogspawn does better than the GSP and the xenia. I couldn't keep either of the latter. The xenia died off (although it came from a tank with lower lighting) and the GSP didn't grow at all. I sold the GSP to someone with much stronger lighting and it grew like a weed. Then again, both these corals were some of my first, when I was using household spiral bulbs that weren't even the daylight type.
Mushrooms will do well.
Two 20W screw-in bulbs would be cheaper, would take up less room, and would give you more lighting. Here are some pictures of my canopy when I was using two types of bulbs (the 20W 50/50s and the household spirals):
I'm going to try four 27W Daylight spirals over my next tank (16 gallon display), which'll only have mushrooms, waving hand, and a head of Frogspawn.
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