dont listen to some of these doom sayers mate. i have used aircraft grade (i swiped from work=oh yea... im an aircraft engineer at aeromil), vibrate resistant nuts for almost 1yr.
it works a treat, as long as you use a nut with the correct NPT you will be sweet.
some guys think up bad situations, they dont offer solutions.
also there is no restriction. compare it to the AFM. a little 3mm bump is better than a 3cm intrusion into the pipe, which a weld in option would use.
just make sure u tighten that sucker so it is firm, DONT OVER TIGHTEN IT.
now u want to find the nuts with a plastic inner lining around the thread. they will stop it vibrating loose, and lock the bolt in place. it is impossible to come loose. ive boosted to 20psi, and nothing has happened, because i have researched and found this to be the best option.