Hi Dave, welcome on board...
Nice bike !!!!
I'm quite happy so far with the White Power rear shox I got for my 1992 900ss. I still have the old shox but its the type with a remote res. and I'm not sure it would fit yours.
I paid £350 for my rear
and am well pleased with the quality although the improvement in handling was not quite the quantum leap I expected.
Good Luck - Frank