I installed a fireplace in our 3075 when had it. I don't remember the manufacturer's name, it might have been a classic Flame.
I had fluted molding on the sides, plinth blocks at the top, and a 1 1/4" thick mantel. I had to enlarge the opening, remove the bottom shelf and removed the back in the cabinet. The converter was on a dedicated circuit and I changed the plug from a single to a duplex outlet and plugged the heater and converter into it. We never had a problem with converter and heater being on the same circuit.