I have cooked on Cajun Fryers before. But, I don't own one. Except for the noise, they are hard to beat. Jerry Blake beleaves in a candy thermometer. But, my PawPa taught me to test with a pinch of meal as well.
I have scortched lots of grease trying to use a thermometer. I don't even try no more. Matter of fact, I usually start turning my heat down once I have it swirling. I also watch for smoke coming off of the grease. There is a difference between smoke and steam. So, beware.
Can't beat experience as Nimrod said.
DP
I am a heterosexual male. 2 Chronicles 7:14
"If my people who are called by My name will humble themselves and pray and seek My face and turn from their wicked ways, then I will hear from Heaven and will forgive their sin and heal their land."