A Nylon expert will be along soon but in the meantime.....
I'd certainly get one of Eddie's NATOs - they are simply brilliant.
The Rhino's are also great but have bulkier hardware than the NATOs.....and, yes, the "original" Rhino is the only one with the patch sewn in. The others are plain.
The RAF/2-ring refers to the single piece straps, whereas the usual NATO/4-ring have a further piece which secures the watch head in place. Eddie's Rhino pics probably demonstrate it better than I can explain.
If it was me I'd go for ...a NATO, a 2-ring Rhino and a 4-ring Rhino.
With a 21cm wrist, you should have no issues with any of the above. :wink:
Cheers,