The front wheel has now had the 21" rim swapped for a wider 18" rim and both rims have been powder coated satin black, with Made-In-England Avon road rider tyres fitted. Finding a 32 hole rim to suit the hub was not an easy task, as nearly every ally rim on e-bay is either 36 or 40 hole.
The fork spacers should be fine. I made them with an interference fit on the inner piston strut and about 3mm clearance round the outside for good oil flow.
Just waiting for my genuine Chinese Yamasaki tank to arrive in the post now !