Actually rethinking my luggage setup... Maybe I could sell the large Kappa. Keep my Givi E21 side cases and use a roll back on top of these. On my trips the topbox isn't used for anything else than a small backpack and a couple of water bottles.

Then I can't lock my helmet in then - But I a steel wire thru the helmet and down to the disc lock should keep the helmet safe. And it is still possible to lock wallet and stuff in the panniers.