They were so mass produced and eyeball put together that 100 of us could give you measurements and they'd all be different. They were just slapped together. Hahaha. As for strength, they're better than nothing but soft enough to pull and bend by hand. I'm sure there's some pulled off for sale around the US. Good luck!
I doubt you'd be able to find 100 CUCV II owners in the first place.
The CUCV II brush guard is completely different from a regular old CUCV brush guard. They are built similar but if I had to make one I wouldn't bother trying to modify a CUCV guard, I'd start from scratch. There are a few CUCV II owners on here that I'm sure will post some info shortly, I sold mine a couple years back so I can't help. From what I remember the bumper isn't too different from a civi bumper, maybe some extra reinforcement for the brush guard. Some of the CUCV IIs had the shackles going through the bumper like on the original CUCVs, but most had shackle mounts underneath the bumper with blackout marker lights on the brush guard.
Also, I know you didn't ask about rear bumpers but the trend I've noticed with CUCV IIs is the Tahoes and crew cab trucks typically have a bumper based on the stock bumper while regular cab pickups typically have standard CUCV bumpers from the 80s.