Tried fitting a couple of different shocks.
Standard GPz shock
R6 shock (15-20mm shorter)
Personally, I think that the standard shock raises the ride height too much and the R6 is a little low.
An NC30 Honda or GSX600/750 Suzuki are possible alternatives to try.
Iím not 100% with the front mudguard so Iíve now got a standard ZXR400 one to paint up and fit.