Jacob,
Seasons Greetings to you!
Very clean, predicated on 22/7 as the inherent ratio.
My personal view of the 28 parts royal cubit is that it was a necessary cannonal after-thought, that the royal cubit length was originally indivisable by its virtue; a linear measurement ascribed by a length of elapsed time and not by the length of a mans arm. I am sure to find many detractors on this point but the arguments against are quite welcome, as there are always two sides of coin...
Best Regards,
B.A. Hokom