Fitting A Burst Nut

[steady41]

I've a QB 79 on HPA  fitted with Wevo tank and Ambush regulator upped to 1050psi  output. I'd like to fit an  1800psi burst nut on on the tank block(low pressure side)for  peace of mind. I reckon it could go on the side of the tank  block(drilled and tapped) picking up pressure from  transfer  hole feeding gun from regulator
   Questions are: what thread type is nut.(3/8 UNF??)  Does the nut have to seat in the drliled and tapped hole, with narrower hole to pick up pressure , or would it be OK to have one dia  hole, and seal using PTFE tape on on burst nut  threads.
   Any input appreciated .