RE: Overdrive 11.0
I expect that since you've gone to the 11.0 m2 rig you are looking for the earliest planing possible, right?
The sail should work quite nicely on the GO 170 (which year model and how wide.... 90 cm)?
Since you are most likely looking for the earliest planing on that board I would suggest upgrading the fin to something in the 64-68 cm range.
Doesn't have to be a "custom" fin, but a bit more fin span always seems to enhance the early planing capabilities of wider boards.
Your board should have a Deep Tuttle fin box, so fitting a larger fin should really be no problem.
Hope this helps,