It seems I missed an important bit when it comes to tuning the new available 7-, 8-, 9- and 10-speed race gearboxes.
I’ve updated the Gearing section in Part 2 - Road Tuning with regard to 7-, 8-, 9- and 10-speed race gearboxes.
TLDR
The new available 7-, 8-, 9-, or 10-speed race gearboxes generally use a higher reference final drive than the Standard 6-speed race gearbox. That means they require a higher final drive tuning than the Standard 6-speed race gearbox for best performance.
Final Drive Offset Reference Final Drive
6-speed 0.0 4.25
7-speed 1.0 5.25
8-speed 0.5 4.75
9-speed 1.5 5.75
10-speed 1.5 5.75