All a matter of personal choice.
My A10. alloy head, uses 8.75;1 GPMs and 357 cam and pulls goes very well and does lots of miles. Does not pink. No issues. But would not want to go any higher, memories of a mates alloy head A10, years ago which was slower and a pig to start and ride with 10;1 when compared with 8.25;1.
Also tried these GPMs with iron head, that was a bad idea, too high, pinked a lot, got too hot.
Have used 7.25;1 which were OK with alloy and iron, but I preferred the GPMs with alloy head.