Was thinking about this thread a bit as I got my Blast pushing harder and faster yesterday
This video is with the stock 44 choco, 6.6 Goya Mark Pro (no cams), and the mast pretty much right on that 130 mark. I don't have video of it later, but I moved it forward about 1/2 a cm after this (gopro died) and it calmed down the front end considerably and felt a little faster.
Hope you got it figured out!
https://streamable.com/jjgkqg
Edit:
Also, forgot to add that I did try the board with the stock 44 choco and the 9.5 Cheetah on a 15mph day and got going fast, but didn't give the sail full rake. It was faster than my 47 weed fin. I think if I raked the sail further back with the 9.5 I'd need to push the mast base further forward than with that 6.6.
I was also getting pretty great upwind angles with the stock fin and 6.6 and would only occasionally spin out from being heavy on the rear foot.