The bolt-on hardtail was not low enough yet, so...

 
...w e cut the lower legs of the bolt-on hardtail to make it a bit lower

 
Aad machined some 30 mm slugs while I cleaned up the rear of the frame

 
The hole in the frame was worn oval so we reamed the holes in frame
and bolt-on hardtail to get a tight fit again, using a thicker bolt

 
Slugs are in place. Check out the bolts that were in the stock frame, these will
definitely need to be replaced...