Drag Racing Tech - Wheel studs question

I have a Moser 12 bolt, with Bogarts wheels with slicks for the track and Budnicks with Nittos for the street.
I have about 400hp and launch at 6,000 off a 2 step. Future mods should put me close 500 hp.
I am thinking of upgrading to ARP studs and want to get the correct size to be NHRA legal and safe.
My question is how long to the studs have to be to be NHRA legal?
Is it ok to stay with 12mm studs?
Any other thoughts I should consider.
Thanks

I've got 1/2" x 3", I think that's the minimum for NHRA, but not positive.

Do think that 12mm are not legal?

The wheel stud spec is based on length. If you use a 12mm wheel stud it has to go into the lug nut the same length as it's diameter...ie a 12mm stud has to engage the lug 12mm deep of threads to be legal. A 1/2" diameter stud must go 1/2" into the lugnut,etc...etc. Some folks run them long enough to stick out on the other side of the lugnut for an easy inspection.