As I needed a pair of mirrors for the FZ1 and had been unable to find some s/h OEM, I went and got a set from Wemoto and to be fair thay look quite good and the rotating hinge and pod joint feel the same as OEM. Anyway back to my mirror mod, I now have a set of FZ1 and FZS mirrors and have come up with a possible solution.
I will approach a machine shop to get them to make up a set of spacers that the FZS mirrors will bolt too and then themselves bolt in-place of the original mirrors. The rubber boot is the perfect size and depth to base the spacer dimensions on and shouldn't require any modification of the FZS mirror base. So am wondering if this bracket will have to be machined or if it can be 3D printed.
So stay tuned.