I got a piece of 1/8" 6061 t6 to use for the radial mount. There certainly isn't going to be an abundance of thread left after counterboring, but it appears to me that it will be adequate. The 1/8" is about 2.98mm thick so I am thinking I will do diet version as it is quite a bit thicker than original. The other option is to sand the piece down (dont have access to a mill) to thin it out a bit and just go with original design as posted by ffkiwi. I am not sure how to proceed on this yet, as I only have a drill press and hand tools. The counterbore is my biggest challenge at this point with making the bottom 90 degrees for the screw to seat against firmly. any suggestions?