The made the Krausers from my 75/7 fit reasonably easily, and they might be easier to find than the G/S items.
My frames broke at the junction just along from the pillion footrest, so if you intend full load / extended off road you might want a gusset plate at the rear of the junction.
And off course a ratchet strap round them to keep the front closed and take a little off the load on whatever latches you have fixing the boxes too the frames.