Currie recommends an auto-front and selectable rear since this setup will have almost zero change to your daily or street driving, but will have some benefits off-road especially on the tight/narrow trails here in AZ. He's got a good video of a rig with this setup where he turned off the rear-locker for a tight turn to show the difference:
I went dual e-lockers since this rig was originally being built for my daughter and we will be living in a snowy climate soon, where having two open differentials is advantageous (especially for new drivers). Had I built these axles for me, I probably would have went dual Detroits. They have some quirks on-road (especially with a manual trans), but they're simple, reliable and once you know how to get them to lock/unlock with throttle manipulation, they're manageable on-road and off.
Unlike
@mrblaine I usually leave both "off" until it's obstacle time, where I then will switch them on as I think they're needed (or sometimes I just leave them off and learn to practice my lines
). This is because as Currie pointed out, turning radius is a mother-f&%@#% with them on. They also tend to "push" when off-camber (just like a spool) so on narrow, twisty climbs you're constantly fighting them to stay centered on the trail. For many trails, this doesn't matter, but if you hit up some of the mountain trails that take you up and over the mountain tops, it can get sketchy.
View attachment 208555
This pic, like many, never does it justice. This is a tight, long, narrow trail that gains >2000 ft of elevation in a short while (starts in the saddle, off-camera to the right)!
This climb starts at the ~25:50 mark on the video. People that have run this with spools are constantly fighting to keep centered and away from the wall or the edge. An autolocker in this situation would be able to be manipulated by throttle application (though not always easy with a manual trans where you're on a constant climb). With a selectable, I left mine off most of the time and where I hit slick outcrops, I turned them back off.