I flew the original 6.x, without G-force. The 6.3 with G-force turned off took the same settings. If you are transitioning from a V4.4, you will realize that the numeric values of settings are different, though the functions very similar. A reasonable start for numbers is for Nose Up to be off. You could use Nose up at the similar to V4.4, but I suggest off. I know some that use Nose up more than sensitivity, and if that is the case, use it as you like.
Try sensitivity in the 20 range and say 80ish more PWM of throttle for Max and maybe 100 down for Min.
G-force off as mentioned.
I don't notice much/any difference in level flying on or off.
When you start with G-force, try about 20. At that I could definitely feel it but not overpowering. G-force is additional acceleration, no additional deceleration. So when you start using it, think of backing down Max, and possibly Sensitivity. But backing down Sensitivity may lessen deceleration.
G-force will mostly change overhead maneuvers, that can include wingover. I also found or imagined some changes in some of more angular maneuvers. I didn't use G-force during the past season as I was happy with using Sensitivity, Max and Min, and was too much of an old dog to learn a new trick. I have now used it for about 50 flights and am getting used to it. In 0 - 5 mph I like it well. I can definitely feel that G-force gives some acceleration overhead. My only flying now is in 45° damp air. Most of those days have been no/low wind. Weather is otherwise wind and rain. When I used it in the wind, I wasn't as happy. But I didn't readjust sensitivity and RPM to get best use. Since G-force gives acceleration, you may be able to slightly lower RPM, and overall, could use a little less battery.
Interesting finding using G-force. It will calibrate, and then if you scroll through the timer settings to change a function, look at the G-force. I fly at about 2.95 with little variation. Today, I was a little slow and a little slack after adjusting the throttle. Interesting G-force was 2.86. I added a little throttle and lap and line tension improved. and G-force was 2.93. Not suggesting that using the number helps much, since you only see it change after a calibration change, usually an RPM change, after the fact. It confirms what you should already know.