I use 500 watts for an oil heater, so that it warms up to 150 watts and does not click, who does not have a 150 watt meter - this is about a 270 ohm resistor 0.5 W, instead of a variable twist.
Got pros:
Works. I put 150 watts on the heater, you can dry things or put a cat in the cold, otherwise the heater is fiery. Clicks, cools, clicks, heats up and so on in a circle. Under my load, it does not heat up at all.
Got cons:
open contacts and rings a little, maybe this is how the thyristor works .See full review