curl up by the fire Mike....

https://www.nasaproracing.com/rules/ccr.pdf

Not sure if rules have changed and Dave has been kind enough to provide a link which I don't plan on reading through so I'll just give you the short of it and hope what I say here still applies.
No cage required for time trials and stock belts are allowed unless you've begun to make changes. If you have started to make the changes a 5 point is minimum and for cars over 3000 lbs cage needs to be 1 3/4" DOM .120 wall. Be sure you read up on cage design.

I have a Miata -- would be just the ticket for you.

For the cheapskate angle, I've got a basic RCI 5-point setup (I think I got it through Summit, which means free overnight shipping where I live)--I don't use the submarine part, because I have cojones in the way . . .

Really, I have adjustable seats without the sub-hole, but for a four-point setup, the RCI belts worked out pretty well (two track days on them). I only accidentally put the horizontal bar behind my seat in the right place (I think), and there has been no discernible movement (laterally) when the things are on and buckled (yes, I just got the kind with buckles, through which straps wrap around the bar). I just fling the shoulder belts off to the sides when I'm on the street, and they don't really bother me; when you put them behind the seat to hang, they tend to annoy a bit. Once you get the hang of the strapping pattern, they're pretty easy to take on and off.

I also like the old-school lever-action buckle, as opposed to the camlock/quicky deal, since my car is older than dirt--the buckle is continuing a kind of theme . . .

I certainly agree with having at minimum a 5 point harness. However, I see no mention of belt width in the NASA CCR. The SCCA GCR specifies a 2" or 3" lap belt.

I am planning to use the Schroth Profil II 6 point. It uses a 2" lap and anti-submarine straps, and 3" shoulder straps. (2" shoulder straps on their HANS specific belts)

I just tried to install my schroth harnesses and the supplied 7/16 bolts are too small. How did you other guys install them?
Hoping for a quick answer so I can run an autoX on Sunday
My car is a'69 Camaro and the belts are profi 2 fe's

You don't really describe what the issue is -- what is "too small"? Too SHORT?? If that's the case you run to the local hardware store and buy some longer ones.... making sure to get the same GRADE as the supplied hardware <most likely grade 8 or 9>.

I used grade 8 fasteners from the bulk section at the local Wilco farm supply store.

If you are trying to use the stock belt mount locations, those bolts are larger. I think I opened up the hole on the brackets for the floor mounted belts and used the original bolts. I had different ones: some had shoulders, some were just threaded as I recall. I chose the smaller ones to open up the holes the least amount.

Also, I think the brackets are hardened which made opened up the holes a challenge.

If you are creating new mount point in the floor, then I don't see how there could be a problem.

Good luck!

Bryan, are your shoulder belts mounted to your harness bar? I think i'm going to pull out my harness bar and weld some "loops/C" to it so the shoulder doesn't slip upon impact. I'm waiting for the Schroth b/o, but MAY go 5pt thanks to the links on this thread. Love hot roddin, just when you think your going one way, bam, fork in the road and you go the other....