Here’s my thoughts on the matter....
Carpets are both terrestrial and arboreal and you need to cater for both. They feel secure on an elevated perch i.e. just below the roof of enclosure and will spend the majority of their time there if the temps are right. I would a 15W heat cord recessed into MDF and covered with a slate tile, to make the warm corner of the base. It will get to around 35 degrees.
Your vents should be placed opposite to the heat tile. The bottom vent just above the substrate while the top vent should be no higher than 750 mm. This allows the top quarter of the enclosure to trap warm air transferred by convection from the heat tile. If this air does remain warm then an infrared globe can be positioned in the ceiling. I suspect a 60W ceramic heat emitter is going to be too hot. A small fluoro will be just the ticket if you want to be able to view the occupant during daytimes.
Blue