I have decided to stop development of this product.
In order to keep the rail in-line with the rail on the receiver the part is very thin and there isn't much space to work with. For this reason I think there will certainly be product breakage and losses that I would rather not deal with.
That said, I am going to offer the CAD file FREE for digital download for anyone that would like to experiment with it on their own.
As of now the ONLY BUIS I have found that fits the tight space is the Magpul PRO.
You could modify the file and raise the rail to make more space but you'd never be able to properly zero in your sights.