I run an 07 gsxr600, and run -1 front and +2 rear (from stock) and it seems good. No need for a lot of top end speed there. I'm pretty sure an 08 R6 would be fairly similar. however maybe others with R6's could give better info.
I've ran there with stock gearing and -1f +2r gearing on my 01 f4i, no complaints with either but definitely prefer -1 +2
Its going to depend on your corner speed. If you're running a good INT (thinking 1:18 -1:20) group pace -1f +2 rear will put you in a better RPM range to get off the corners. Like T6 if you're going down to 2nd. Then short shift to 3rd at the access road. As you pick up corner speed, youll find going to -1f +1r you can hold gear longer in certain spots for an advantage. -1f +1r also works well for me at ACC.
I always liked -1 at BHF. It worked very well for me. If you haven't been there before, it may be best to just stick to stock gearing and figure out what you want more of based on what gear you want to be at in certain turns (IMO)