I am interested in your adapter rings if they are still available. But first a couple of questions. From the photo, it looks like the front of the ring extends a good centimeter or so beyond the front of the lens itself. Is this correct? Have you noticed any vignetting on wide lenses (say below 24 mm fl) on Epic/Scarlet or RED One? My widest lens is a Tokina (Canon) 11-16 with 77mm front threads, though I have yet to actually use it on my brand new Epic. But I just wonder if a good bit of the zoom range would be lost with something protruding in front so close to the thread size of the lens itself.
I also have a Canon 16-35 with 82 mm front threads, and I just ordered a new 85mm adapter ring (which should arrive in a day or so) for my Petroff matte box to try to fit that lens. The problem with the 16-35 is the classic problem for still lenses generally and which your ring is meant to solve . . . i.e., the lack of consistent, flat, friendly contours on the lens housing for a matte box collar. This particular lens has a curve to the flange (viewed in profile), which looks to be especially problematic for a secure fit. So a screw in adapter ring with a nice wide, regular flange like the one you're offering seems the perfect solution. My only concern, again, is vignetting. My understanding is that 85mm is the next common step up in cine lenses, and it is the next size up from 80mm that Petroff manufactures in standard size adapter rings for its matte boxes.
What would be most attractive for me is one of your adapter rings to fit 77mm front threads but with an outer diameter of 85 instead of 80, which should be wide enough that vignetting becomes moot. Then I would also need a version stepping up from 82 to 85. Any chance you could make those (or have your supplier make them)? I have to think this would be of interest to others since I imagine all the new RED users that are employing still lenses (most of which have 77mm fronts and funky outer contours) are going to have to deal with these same issues.