I think you are right use the E-Maxx 3905 setting.
It actually says in the manual that the tranny plus diffs is a 5.22 ratio. So that is what I have been plugging into the calculator along with the pinion and spur settings.
“Everyone has a right to be stupid; some people just abuse the privilege.”
Yeah - 5.22 is the ratio of the diffs and tranny combined. Would be nice to try and figure out the ratios for each, but the parts listing for the ring and pinion gears don't give numbers. Looks like there are some tranny option parts available that will allow you to raise or lower the gearing ratios but I don't really see the point with the variety of pinions and spurs available and it being a one-speed.
“Everyone has a right to be stupid; some people just abuse the privilege.”