Pendantic.... that is a big word LOL.
While you might want to do some pre-loading of the head's threads, IMHO insert the stud right away, so the sealer/locker will flow and fill nicely around every thread. Then let it cure for at least a day before loading the stud.
As for the temp? My pure 1000% guess is halfway.... 400F LOL. BTW those IR temp guns have a spot size of their 'view' so I doubt you could focus on just the end of the stud.
Permatex data sheet:
https://441py33rout1ptjxn2lupv31-wpengine.netdna-ssl.com/wp-content/uploads/tech_docs/tds/59235.pdf
