Heat cable is not ideal, due to inconsistent heating, but with a thermostat and a heat gun it is fine.

I have two that I use for backups when I have a snake on top of my rack as a temporary housing situation.

You cannot use a rheostat and then critique a heating element, you need a proper heat control product (thermostat). I would use a dial light dimmer for 3.0$ before I would use a zoo med rheostat.

Bruce

PS: not ripping on you.