I tried the +35mm ones from OTR on the Z and they indeed raised the rear by 3.5cm, but made the handling horrible. Without being able to raise the front easily, I'd be wary of over-doing it at the back. The geometry will change quite a lot for a very small increase in height at the rear.
The main issue I found was that because the swingarm was at a steeper angle, the rear end tended to squat less on accelleration and caused the front to go light (and wobbly), and at the same time less squat under power reduced mechanical grip while on the throttle. The steering was slightly "quicker", but nothing too extreme. It was the sensation of an imminent "tank-slapper" when accellerating that put me off +35mm.
In the end I settled for some
Projection Components 4-way adjustable raising links, so I could play about and find what's best. They'll raise either, 5mm, 15mm, 25mm or 40mm. In the end I found that (with correct sag) that a rear end lift of 15mm was as far as I could go without an adverse effect on handling. (I don't think they do them for the R/X though?)
Now, everyone is a different shape and size, prefer different handling traits and have different suspension setups to suit, so realistically the only way to find out what works is to give various heights a try. The R might behave differently to the Z too, so bear that in mind. Links aren't that expensive to "buy and try" and are actually pretty cheap to get machined up at the exact length you require.
You get a piece of paper with the expensive ones!
