Thanks much. I've finally decided that over thinking had become my enemy. Instead of buying an Outer Banks w/ Advanced 4WD and 4.27, then lifting and adding bigger tires and worry about driveline wear, proper driveline angles, gearing, gas mileage, etc, etc, etc, I'm going to change my order to a Badlands w/ Sasquatch. It's as high as I need, upgraded front diff, drive train components/35" tires all designed to work together, full underbody armor, factory warranty, and so forth. Most of our wheeling will be solo, and as such being properly equipped is very important. Gas mileage will be what it will be. Mrs Contented finally said "you'll be sorry if you don't get everything we need now". That was all it took.The axle size and spline count (more spline count is also larger axle shaft diameter) aren't dependent on the gear ratio, but the spline count of the side gears in the differential. Both the M190 and M210 have 29 spline axle shafts. It is yet to be learned if the axles are exactly the same, most likely they are. So, this would mean that while the ring gear is bigger in the M210 than the M190, the axles are the same. What we also don't know is what exactly is the upgraded axle shafts offered in the Ford dealer accessory catalog. Would really like to know what kind of an upgrade it is.
The rear M220 uses 32 spline axle shafts. Also, the D44 FDU complete from diff offered as an upgrade from Spicer is an M220 diff and uses 32 spline CV axle shafts. We still have some things to learn for sure.
Once again, thanks to all.