Heat Panels?

[Malum Argenteum]

A couple more things. In addition to the RHP, you should use a UTH. I use heat tape and it works great. The heat from your RHP won't penetrate your warm side hide very well, so you'll want heat coming up from below.

Good point to consider, but not necessarily true for all enclosures and might need some testing in the specific enclosure in the specific ambient conditions.

I don't use heat tape on any of my PVC enclosures that run RHPs, and even the ones on the bottom of the stacks (12" and 15" tall units) don't have any problems keeping the warm hides in the right temp range. It looks like your viv is considerably less well insulated and more ventilated than stock PVC enclosures, and you're also not using substrate that can help to both insulate and even out enclosure temps (the latter by acting as thermal mass).

Also, in situations where the enclosure is near a cool floor and that is complicating heating, a sheet of insulation under it can make a big difference and do so more simply than running heat tape. Just another option to consider.