Yep. Keep that temp gun handy. There's no use to have an engine running slobbering rich on the starter box with a huge puddle of fuel beside the stinger.
Back in the day when I got my first ABC engine(HPI .12R, anyone remember those?), I idled it so rich I could hold my hand on the head forever, and this continued for like, 8 tanks. I thought that was the thing to do. Well, the engine lasted forever (I still have it today), but never reached its full power potential. When I rebuilt it earlier this summer, I installed a new piston and sleeve set...same conrod, mind...stuck a new MC-59 plug in and idled that puppy for one tank, adjusting the carb so that the temps remained in the 200F range. Tossed the now-contaminated plug for a fresh one, installed it in my XXX-NT along with an AE pipe, and ran it. Temps stayed in the 220F range for the first gallon, then it woke up.
Truth to tell, even for a rotary-carbed, side-exhaust engine with "only" 1hp, I'm afraid to lean it out to full race temps (240-260F) because the truck is barely controllable as it is.