I run 3 tanks on a stand, slobbery rich, so it barely runs without dieing, about 180deg.
Then run it around the yard giving it short bursts of throttle once in a while and leaning out a little at a time so it still barely runs without dieing, 3 more tanks. 200 deg.
Then it’s ready to take to the track, I run it rich so it barely clears out down the back straight. 2-3 more tanks.
Then it’s ready to set the needles, I run it as rich as I can allowing it to clear out quickly on acceleration, try to set it between 230 -240 deg.

Hyper .21s have a tendency to run hot 230 -260 after full break in, cooler is always better
The first one I had lasted a very long time, I have 2 others now, they work great,
Have fun