Not enough flexibility Andy. If you accept the need to lift the rear of an MC18 as standard and are contemplating a swap to 17inch rubber, I assume the plates offer no allowance for both. What was it designed for? A 17inch wheel swap, a useful lift in the rear for track use, or both?

Dunkenb the 21 plates are just too shallow to compensate for the shock length

We have tried rotating the plates in the track bike and gained 10mm from memory which dosen't sound like much but felt like quite a bit on the bike. Not enough here to help with the wheel swap.

I think the easiest thing would be to put the 100mm (ie 10mm shorter) linkage arm in and take the extra rideheight after the 17 goes in as ballpark. If the arm adds 40mm and the 17inch wheel swap drops this by approx half of 27mm that gives a 26mm increase at the rear and there are plenty for sale thru Yahoo Japan. This is measured from the very end of the swingarm to the bungy hooks. Perhaps 26mm is too much, haven't tried it yet.

Its a simple thing for an engineering company to thread some Hex rod (although its a reverse thread at one end) and then buy some rod ends to suit. Thats all the adjuster is although it would be equally easy for them to make the plates I guess