What i would do is take the hub and put it up against the back of an APC prop and see where the hub sits or how much the prop overhangs the hub.
Anything above 40cc i usally like my face about 1-3/8.But im usally running wood props wich have a larger diameter center.APC and some zingers are smaller.
The center portion of my 17x8 APC is 1-1/4 in diameter.
I also looked at my BME 21x10 and checked the back of it to see the marks left from when it was mounted on my G45 and the marks are only 1-1/2.This was a stock G45.
So i think that youd be OK.But if you want i could make you one.I could make it the same way but theres no point if your only going to gain 1/8 to 1/4 of an inch.
And theres no sense in making a huge hub with excess sticking out from behind the prop.
Ill send a PM to av8tor or yu could and see what size hub his is and i dont remember what prop hes runnning.Hes starting a second one.
I went and looked at the one in that thread.