Had a Givi BF02K ring laying around, and with a ZT4802R flange and some M5x25 bolts it mounts right up. Gas cap access is not compromised, and with the larger of my two bags there is no interference at full lock. Felt a bit guilty not using torx bolts though.
That looks a lot better than the one that is called for on our bikes, the lip is more than twice as high as what you show. Have to order that up this weekend.