I don't think this will help you but you do want to make sure about fitting before buying. I use Gunfighter on all four of my DPMS LR-308 uppers and lowers with no issues. When I built a Aero M5 the Gunfighter worked in that upper when that upper was on a DPMS lower, but when I finished the AERO lower and put the two together, the BCM Gunfighter would no longer work. The bottom cut out on the back of the CH would not clear the wider receiver extension boss on the Aero lower even though it worked fine on the thinner boss of the DMPS.
What I had to do was use the PRI Gasbuster CH.
Now, I know nothing about the G charging handle, but you could have knocked me over with a feather when the Gunfighter would not work with the Aero M5 lower. I never would have dreamed such a misfit, especially since it worked with the Aero upper on the DPMS lower. Who'd have though the lower would cause a problem?
Anyway, good luck with the G CH and I hope you will post what you find out about it fitting.