[yossarian19]

IIRC all the Dana axles use shims to adjust backlash / pinion depth.
A word to the wise is to use a brake or piston cylinder hone on a cordless drill with the old bearings & open them up until they can go on / off the carrier and pinion by hand.
This way you can go back and forth a few times making sure you have everything set up correctly before you need to press bearings on.
Ideally, you'd buy two new sets of bearings from the same manufacturer and hone out one of the new sets. Might be worth using a micrometer and measuring the difference in thickness between the old ones and the new set, though, if you aren't going to buy a double set of bearings.

As for ratio...
Depends a little bit on your tire size. 3.55's are probably a safe bet but I would google search "tire size gear ratio rpm" and find a calculator online. I can say that my old Jeep Cherokee with a 29" tire and 3.55s spun about 3K RPM at 70 mph while in third gear (1:1 trans ratio).