I've seen 8 to 8.5 threads of engagement as minimum for 7/16-20 threads. I've found lug nuts go another turn or two when seating them all from hand snug. I would install a wheel, all 5 lugs torqued then remove one and count the turns to tight to be sure.
Tire rack says number of turns engagement is 9. I have not checked it yet but why would they sell these wheels for small bolt pattern if stock studs didn't work and you cant get longer ones idk anymore lol.