It all depends on the type of rider you are, +2 or 3 on the rear for Broadford, stock for PI was what seems to be what most people run. I think as you adapt to the bike your ratios may change slightly.

As for tyres, AFAIK proddie tyres like the old Alpha 10s were the choice, I haven't talked to some riders recently to know if they run slicks or not. I know you struggle to find slicks for the 250s.