In this game, you can spend a lot of money, and it's true, if you invest in an expensive I2 system, you shouldn't skimp on the support gear. But I would also submit to just get you started, the humble issue stuff does still work. I ran this system for many years and it served me well.
A couple of tips. You might want to place some sticky back velcro or even closed-cell foam in the space in the center of the shroud. Depending on your mount, it may have some play there and the extra material will firm things up. And again I'd run bungees, just to keep everything under tension, so it doesn't wobble around. With the USGI J-arm, I'd run a single bungee, so it can sit under the release tab, to prevent it from opening and dumping your unit.
Attached FileHere is that whole system assembled. Notice bungee under latch; misc pull tab added to fill up gap and prevent activation. Also notice johnny-home-maker lanyard, Simple field expedient, a micro "s" hook and a hank of paracord. You just tie an overhand knot in one end, passthrough hole in -14, and tie a bolen knot on the other end. A piece of elastic keeps it from unravelling and silences it. Another short piece of para cord, with an overhand knot on both ends, sits underneath the shroud, creating a loop for the hook.
Also notice hole in BC #07 cover. This is your "re-focus" ring. Notice I also sanded off BC logo, and bead blasted the whole thing to flatten it down.
This rig served me well in lots of training and classes. Never had it pop once.
Finish is custom-mixed Duracoat. Back then I was mixing in earth brown tones. I think it makes sense to coat any bare plastic or metal. Sorta depends on what your up to. And opinions do vary.