Tabuk Sniper Build Underway - Need to Settle on a Scope

I have a spare ONM76B scope and there’s a real outside chance I may have a line on a x39 elevation cam/drum for it but I’m not holding my breath. I understand all variety of optics may have landed on these rifles in Iraq but I think they typically carried ZRAKs (ONM99 – unobtanium) or PSOs. While I’m a huge fan of RSRegulate side mounts I don’t think slapping a Trijicon or other modern optic on this thing will be remotely appropriate.

Many years ago for my PSL I bought from Kalinka Optics a: “PSO 3-9x24 Tigr, 1000m Rangefinder, SVD” from Kalinka. It's a fantastic FFP optic. No longer available of course .

In summary : Where does one go to source a side mount ComBloc type scope cam’d or BDC reticle for 762x39 (and a 20” barrel ???) that’s going to be a decent fit for this build? 4x or 6x, fixed or variable (FFP), would be great. Don’t care about illumination. PSO New POSP? Kalinka? Belomo ? Looks like they sell the same thing. Both Belarusian optics? What is Valdada? Am I looking for a Simonov reticle ? Plenty of modern BDC reticles for x39. Need Combloc side mount.