Heating In a Glass Enclosure For a Snake?

I have recently brought home a Children's python and would like some opinions on heating his three foot glass enclosure (two feet high) as I know all-glass enclosures suffer from heat loss.

Currently it's heated with two ceramic bulbs (on a thermostat) on top of the screen mesh lid. The back has a Styrofoam background. Coco peat substrate.

I'm going to cover much of the lid with a piece of Styrofoam. Would covering the sides with a Styrofoam background (or something else) help too?

As for the heat source, are the two ceramic bulbs alright or would I be better off having something like a ceramic bulb and a heat mat on the bottom (if I do this, I can't run them on the same thermostat, correct?)?

Thanks for your answers and your patience with this newbie!