Max G will be bounded by excess power available for a given velocity and onset of blade stall. In other words, if your aircraft can fly strait and level at a given airspeed at 10,000 pounds gross weight and has enough excess power to also sustain level flight at the same airspeed at 20,000 pounds gross weight it should be capable of sustaining a level 60 degree bank turn (2G) at that airspeed, assuming it doesn't run into blade stall. Actual structural limits are a different animal.