Not for nothing, but I’ve found much better success with polyurethane 112’s. I got the suggestion from Wayne at Amigos in Ft. White, FL, and I’ve since had it confirmed by both DGX and Deep 6, who both kindly gave me o-rings to swap out. My guess is that the DIN rings wold work the best, but it’s easier to get the PU 112’s. I went from the rings popping out two out of three times taking it off the tank to never in 11 months. (The frustrating thing for me is that mine were the factory o-rings: I think my knockoff regs use the Apeks DIN gland but 112 o-rings. Yay knockoffs!)
I’ve also given away rings to at least three Apeks divers in the last 6 months: this seems to be a common situation for us non-EU divers...