I have chosen to make my grips myself from several layers of leather to have something special the advantage is that it impossible to take the grips off.
1. Measure the dimensions your pieces will nee to be ( you best measure every layer apart because every layer will become bigger.
2. Sew the peaces together (yes by hand) with a thick needle and hight quality wire ( don't pull too hard because leather can rip.
3. measure and sew the sides of the grips ( it gives it i finishing look)
I used a some material so the grips won't move, a lear of thick, soft leather for the centre and a smooth hard leather for the outside that will fit the colour of leather of the rest of the bike.
It is normal that it takes a long time to do these grips it took me 12 hours for the both of them!
The pictures gives u an idea of the result the kind of stitch pattern is of course to your own liking.