So i went stock measurements as they were pretty well the same as the oculus I had from them. It has been pretty solid. Yes I can pull out and accidentally did so once when all soapy giving a good cleaning. The penis can be very squishy I might could go a mm smaller on the ring but haven't gotten the guts to make another. Mark sent me an extra piece of the ring with instructions to make it work. However, once I get aroused it's darn locked in place and unless it's extremely lubed up, it ain't coming off. It is definitely an interesting feeling when I get hard.
I'll add, this has been a wonderful change for me. I've been able to practice soccer, do yard work and everything I need to get done without any fear of getting hurt. Cold morning are no longer painful and it masks itself pretty good under leggings.