If you removed the magazine cycling mechanism on the right hand side then you would have equal access from both sides of the breech. After that it would merely be a case of slotting in a tray with a groove cut in the centre to allow for a pellet to be dropped in mimicking the HFT500 breech

This would allow sx10 owners to fit large diameter sidewheels with no loading access issues!
For neatness sake you could easily machine a cover for the exposed side of the bolt utilising 2 of the three preexisting allen bolts.