CR-10s Pro - CR-10 Max z-sync - various belt length possible

For my CR-10 Max I did my own kit which allows you to use belt which different length (approx. 1200mm to 1600mm). This Kit only works with the “on top of flipped brackets” pulley setup, but is very minimal and creates not unsymmetric pulling force on the top of the leadscrews. 
Note: for the CR-10s Pro you just need the 2x GT2 20T B8 W6 pulley and a 760mm belt. If you cant get the belt length this setup should also work for the CR-10s Pro with belts from approx 900mm to 1200mm

Shopping list:
- 2x GT2 20T B8 W6 pulley (6mm wide, 20 teeth, bore 8, with grub screw) 
- 2x GT2 20T B5 W6 idler pulley no teeth (6mm wide, 20 teeth diameter, no teeth, bore 5, idler)
- 2x GT2 16T B3 W6 idler pulley with teeth (6mm wide, 16 teeth diameter, bore 3, idler)
- 4x M5x10 bolt
- 2x M5x20 bolt
- 2x M5 washer
- 4x M5 T-nut
- 2x M5 nylock nut
- 2x M3x15 bolt
- 2x M3 washer
- 2x M3 nylock nut
- GT2 6mm closed timing belt approx. 1200mm to 1600mm (I used the 1220mm long ones)

assembly can be seen at the pictures, but is somehow straight forward.

on top of flipped brackets: the top leadscrew brackets are flipped and the GT2 20T B8 pulley is installed on top (see picture). The leadscrew needs to be pulled out of the leadscrew to stepper motor connector a few mm