They articulate just fine off road. Just use one leveling valve in the center of the hogshead to run both air bags. Using the center of the hogs head as a single pivit point (like a seasaw). As long as it is satisfied with the hight is all that matters. So that means that one bag can be almost fully compressed and the other bag can be fully inflated and the ride hight valve (center of hogshead) be in the same hight position throughout the range of articulation. If you were to use two leveling valves (one for each air bag) the articulation would be compromised greatly due to each bag being in a fixed position. (Be hard to seasaw with pivit points on each side). And I have known guys doing this because of a truck being off level. Getting the truck to sit level can be a bit of a task since the frieghtliner suspension is set up for pretty much evenly distributed weight. Whereas the Deuce has both the fuel tank and the batteries on the same side and is relatively light in the rear in comparison to a road tractor. My truck leaned really bad at first and had to do some tweaking on it. To where "Cidrich" truck sat perfectly level from the get go and they were both built the same way by him. The freightliner airbag travel is close to 12 inches. Your not going to get near that out of a leaf spring of that rating. Plus makes it's nice to load stuff when I can drop my bags on the truck to make the bottom of my bed a little over 5 feet vs. 6 1/2 feet off the ground.
Ditto. Sometimes a little out of the box thinking is required along with a bit of imagination. None of this is rocket science. Also there is absolutely nothing special about a deuce when it comes to suspension or customization. Its just a truck. Almost anything you can think of has already been done. Maybe not to a deuce, but it has been done none the less.
In fact there is absolutely no difference between installing air ride on a deuce versus an otr truck. None. They both have the same incredibly basic ladder rail chassis design that hasn't changed a whole lot in 70 plus years.
Since the op has an m36 and plans on it being a mostly otr truck it would be incredibly easy. In fact a neat idea, since you will have the extra room, would be to spread the tandems a few inches and mount 14.00-20 tires. Then you really would have an awesome rig.