Is an RHP Necessary in 2'x2'x3' Enclosure?

[Scubadiver59]

I'm looking at an intermediate arboreal for some of my juvenile climbers, namely a Dominican Red Mountain Boa, a Southern White Lip, and my Malaysian Red Tail Green Rat.

The enclosure will be .75" pressboard w/melamine laminate inside and out--I use these materials for my 4'x2'x20" enclosure--with a plywood front side w/plexiglass front door, again, same as my larger cages above.

I'm thinking of using a 60w light and a CHE at at the top...but will that be enough to keep temps up? Or should I go for a small RHP mid-enclosure?

Inquiring minds...