A thermostat would be better than a dimmer to regulate. ( prefer to place the probe directly on the heat tape outside the tubs, the snake can't move it out and getting the temp get crazy since the probe is not recording the right information).

In my rack, right now, my thermostat is heating only at 10% to keep the temperature at 95, so the inside of my tubs are at 90-92 (depending on the level).

btw : the plants are nice, but does it have enough space to crawl ? a BP prefer to be flat. I suppose the plants are not taking all the bottom surface and it give it some hides so

and make sure those clip are enough solid.