Some 1mm washers with a 15mm centre hole should do the trick.
Before that is done id suggest getting the sag set correctly front and rear (if you havent already done this) this could sharpen the steering up as well.
Another thing you could do to have the same effect as raising the rear ride height is to lower the front end by raising the forks through the yokes, try 5mm to start with.`
I did mine, put a 2mm engineering shim in that I got from a quality engineering supplies shop. Dead easy, quick job too. When you have the shock top undone at the top mount , I packed some rags around a car scissor jack which I sat on top of the rear tyre an very gently wound the jack on until I could get the washer in.
Definately improved the handling but if you have short legs you have to ride like an Apache Indian dodging bullets to get your knee down.
You will need to check your sags again , front and back, when you’ve done it…weight’s shifted slightly.