Help with heating... PLEASE

[peterm15]

ok.. heres what ill be heating...




and theres gonna be a third non attached enclosure on top for a ball python.. the 2 attached are for corns..

so above heat is not an option.. and putting het tape/pad under prob wont do much with 5/8 ply.. but i can put underbed heating INSIDE the cage under glass or tile or something ( all glass and tile i have on hand.... and its all free) is this a good idea.. and if so what method should i use... heat tape or pad or reptile heating pad... i plan on setting everyone up to a dimmer..

if its heat tape what size should i use.. 4", 11" what.. and it should cover about 30-40% of the cage bottom right..

please i need some help.. the quicker this is finished the better.. its taking up space not being able to house anythin in it.. lol..
Thanks alot

oh and p.s. the dimensions of each enclosure is 36x16x12.. well for the ball is 36x16x10.. so.. thanks for any help..