In the mean time before you get a chance to put custom valve stems on, you can still properly maintain your tire pressures.
I added short extensions to the outer dual, and use the following process to check & add air (78% nitrogen!):

I can move them to any wheel I want when I rotate the tires.  I just completed this task a month ago as I had a vibration develop in the front right on our last trip.  I pull the wheels & haul them to the tire shop for balancing.  I reinstall them where I want, and I ensure the duals are properly installed, that is, the sight hole in both wheels is lined up with the indicator in the hub, and the stems are opposite each other:

Here's my 
Pressure Checking Process in pictures.