cppa and tti are not the same header or company.
Welding your own headers are hard, fustrating and extremely time consuming.
A thick flange is all you need for a leak free header flange. If it is not thick, tighten gingerly and recheck once in awhile.
No need to O ring.
I have headman eliete headers with the ball and flange set up.
LOVE IT!!!!!!
Tighten up well. check on it a few times after intinal install. It's gotta be tight.
Never needed locking header bolts. Post on what you find.