Looks good, Larry!
As you know, I tried one of his Gen I backs on my EXPII but the dimensions changed the way the watch sat on my wrist so I put the steel back on.
I also ordered one of his display backs for my Omega SMP and he sent me the wrong size (mid-size). Eventually he sent the correct back but the edge-to-edge diameter was .5mm too large which prevented the back from screwing all the way down for a seal. Fortunately my watchmaker was able to machine the edge down and make it fit. (The machining cost me an extra $50.)
I hope someone will install a Gen II on an EXPII and provide measurements for a comparison with the OEM.
Fr. John†