Gotta remember that synthetic burns a different colour, Grey, like yours. But you want a lighter grey than that. Build up on the end of the threads is a good indicator.
Mineral oil likes a chocolate brown, but synth will never get there. Plus you've got to remember most of those charts are for 4-stroke cars too eh.
44 to a 32 will really lower your rpms for cruising, good call. Hope you don't have any big hills