A quick update for those looking to regear/add lockers. As it turns out, I have a 32 spline axle in my rear Dana 60 and Eaton does not make their ELocker in that configuration (they have 32 and 35 spline). My front Dana 60 Kingpin is a 35 spline. So my options were to go with an ARB air locker in the rear or go with an Eaton ELocker in the front. I could have changed out the rear axle to 35 spline but that would add a lot of $$$. I could have also gone with a limited slip like the Eaton TruTrack or an auto locker but decided against it for various reasons.
I have opted to go with 4.56 gears and an ARB locker in the rear. I will run the front diff open and have the option to add an ARB locker in the future to the front if I feel it's needed. The 4.56 gears will put me at 2340 RPM at 70 MPH in overdrive, which I think is reasonable for highway cruising. The cost breakdown is: Labor is $1330 and $2520 for the parts
By the way, the Kingpin Dana 60 with high pinion is a very highly sought-after axle . I was unaware that was a thing.