I chose to have Chuck "Tireman" extended valve stems put on. (I believe Borg also makes the same basic type.) These are a rigid product that basically IS the valve stem, but is longer and custom bent to fit the rig perfectly, has no extra "joints" to leak, and makes it easy to check or add air to tires on DRW rigs. I chose to go to "Tireman's" shop in Ridgecrest, California, and have them put on by Chuck himself, but you can also order the kit from his website and have a tire shop put them on (there are instructions available on the website). Here is a link to the kit I put on my rig - there are other kits available on the site as well:
http://www.ridgecrest.ca.us/~tire-man/kit2.html
If you do go to Tireman's shop, he's put a lot of these on E-Series cutaways like ours, and even has shady parking available if staying over in the rig fits the schedule best.
The kit also includes "air through" caps. These are like the protective caps you normally put on the end of the valve stem (and then remove to add air whereupon they roll under the rig just out of reach
Here is an overview, showing the rear with the Tireman stems. One minor detail/tip from Chuck that I like: He always mounts the tires with the DOT date code right by the valve stem. Easy to keep an eye on without having to hunt for them as one usually does.
********************************** (explanation of inflation chart here) (rest of post in replies, below)
*These recommendations go by tire size, and by actual loaded weight on each tire, not by "door sticker" or the max inflation per tire. Basically, you weigh your rig (which is good to know in any case) by axle, and then divide that figure by the number of tires on each axle (to get weight per tire). Note that you want to inflate all tires on a given axle to the same psi, so don't "individualize" them but rather just divide axle weight by number of tires on that axle (if your weights are really off side to side, then it's better to adjust the load in the rig to even them out). Then you look at the appropriate chart and inflate accordingly. This matches the air in the tire to the load (which is the whole idea behind inflation numbers). Here, for example is a generic chart for the size tires I have on my Concourse:
