RHP placement, wattage, and lighting

[Dark Lady Kat]

I need to know which RHP is better for each of these two size cages

6'x2'x1.5' i was thinking 120watt RBI

4'x2'x1.5' here was thinking 80watt RBI

also should it be placed centered to thoroughly heat the ambient temp or on one side.

If on one side should there be an alternative heat source for the cool side to raise it above 70

my average household temp is 68-70

Which thermostat is best and is it best to have one thermostat per RHP per Cage

When using RHP what is best for day night cycle lighting and also night viewing all to be contained with in the cage