Yes, cypress is safe for BP's. If it is packaged for reptiles, you don't need to cook it, but if you are getting it from work, you should probably cook it to kill any bugs off.
Can't answer your question about the 55, I've never used one for a snake. My 75 gallon aquarium has one ceramic heat emitter (75w) and one UTH at the warm end. My boa is in it.
"Redtailed Tree Boa"?????
Do you mean a Red Tail Boa (BCI) or an Amazon Tree Boa? Big difference!
My Jazzy is a BCI. There are pics in the Tree Boa forum of an ATB.