The amount of Gs pulled in a turn is controlled with the Turn Factor property, which will scale the size of the curve that the airplane will turn on. The Turn Radius Expansion Tool is a calculator in which you specify the Altitude, Airspeed, and the Load Factor G or related values to determine the required Specified Turn Radius Factor. This calculator will limit the turn factor available based on the Load Factor G value of the current acceleration performance model; click Change... to edit the value in the performance model from this window.
The turn factor is always stored with two decimals of precision; the actual Gs pulled may not be exactly what you specified.