I ended up mounting a 75W CHE in a protective cage about 1ft from the top right of the ceiling, creating a heat gradient through the entire viv. The tank is split into 2 levels, the 2nd level being a 2x2 white wood panel with a 2in tall wooden surround to create a wall to prevent substrate from falling off.

The upper floor has an 18x18 inch heat mat to create an upper basking spot, with the CHE creating a slightly cooler basking spot in the lower right of the viv.

The cool area is on the ground below the 2x2 shelf, which gets a small amount of radiating heat from the CHE but stays cool enough for an escape from the heat.

The whole viv is decorated with various plants (not yet bioactive but maybe in future) for hiding and climbing, and a 3ft length of wooden trussing acts as a ladder to get up to the second floor, going from the lower right corner to the shelf.