Recently I received a care package from Dr-Zocchi (highly recommended) so I can rebuild some of my forks, this included an FS to IS adapter for this project.
I can now test fit the front brake, this showed that a little material needed to be filed off so the the bolt holes would line up. It does look quite neat.
This caliper is a bit crusty and the pistons appear to be sticking a bit so requires a service. I have another caliper with stripped threads which is in better cosmetic condition and thought I'd play with some helicoil, if successful I can rebuild this caliper instead.
The helicoil worked OK. I did drill out the threads slightly wonky and it was quite difficult to get the coil to screw in. The other problem is one of the mounts is slightly thicker than the other which means the coil comes out the back by half a turn. As I wasn't happy with I removed the coil, cut 1 thread off and installed it again which now looks a lot better. This caliper is now usable, even with the slightly wonky holes!
All I need now is a caliper seal kit, hoses, chain, better chain device and to service the forks.