now i read up, i feared my post would be totally nonsensical because i at first missed the first 6 post, but its not too bad.


about the mystery of how they do it with unregulated heat sources:

it can be possible, but i can only think of exactly one option: You need to buy a heater with extremely low output. like 5 watts, 8 watts, or 10 watts. if the maximum output is very very low, it basically works like a more powerful UTH on a dimmer. but you need to test-run, you need to use the ones with extremely low output, and when it gets too hot there is no dial you can turn to fix it, you need to replace the UTH with one that has a lower maximum output levels. i think thats the secret, instead of dimming they use heaters with an extremely low maximum energy output.