All good guys I have worked it out on my rotary table on my mill.
I will end up with 8 settings 0, +4, +8, +10 (might change to +11), -3, -6, -9 and -12 Degree adjustments.
The Optional Cam Sproket 13024-E4621 has the following: 0, +3, +6, +9, -3, -6, -9, -12 Degree adjustments.
Hopefully it will give a bit more adjustment to allow for closer cam timing
Justin