you can run it at max joules and you should be bale to run max temp
if for whatever reason temps over 500 taste burnt or are so hot its almost impossible to cape you are having an issue with resistance readings.
I find I can run most of my stuff at 450-500F at 50J.
If you drop temp below 375F you may run into issues with it not firing saying DRY COIL or whatever message the SIG uses .
I find that at 400ishF I get the same temp form a .5 kanthal coil at 20w