I, too, have similar questions for my V1.
I'm getting a newer style V1 bottom end with a needle bearing crank. While it's all off and apart, I plan on case matching it to my 75cc Polini. My theory (please correct me if I'm wrong) is to use a high compression head to 'offset' the lost case compression due to the increase in volume from matching.
As far as I know, there are two high compression heads for the V1 (courtesy of 1977 Mopeds):
1. Garelli High Compression Head, 48mm diameter
2. Minarelli High Compression Head, 56mm diameter
Which head would you prefer/works better with the 75cc Polini? I am leaning towards the Garelli one since it is designed for 48mm pistons (Polini kit = 47mm), whereas the Minarelli is designed for 56mm pistons. Any input is appreciated! Thanks in advance.