Ron, rather than mess with the long stems (yes there is a set made for the Alcoa wheels) and the associated issues (proper torque of the retaining nut, easily torn seals during installation, difficulty in installing the duals without damaging the stem of the inner wheel as you attempt to put the outer wheel in place and get lug nuts started) consider using the standard short rubber 80 psi rated truck stems like you are using now, and use a long stem tire servicing chuck and a long stem gauge. One with a straight end and a angled back chuck would probably work well.
THIS POST Shows what I am referring to. If you opt for the long Borg stems, especially on the inner wheels, be sure and carry a package of spare seals for the stems, a small tube of blue locktite, and a tiny torque wrench and proper socket), as changing a tire on that wheel requires (depending on the tire machine used) removing the stems, then removing the tire, then installing a new tire, then re-installing the stem with new seals, and finally inflating the tire. Again, this depends on the tire machine design, and you never know what you will encounter on the road.
Charles