BTA's live in the rock and can easily be placed higher toward the top of the tank, in which case your lighting should be fine. Sebaes (whether it is H. crispa or H. malu) tend to be in the sand bed as they like to bury their foot. In which case, I would be inclined to have four 54-watt ho bulbs. You might very well be able to get by with two, but 4 couldn't hurt and would likely benefit the anemone. Also sticking exclusively with daylight (6,000K to 10,000K) would yield a higher PAR and insure your anemones are getting the most photosynthetic activity per watt.