It woudl be much easier if my hands were not xxl (or is it xxxl) but I am able to inflate mine using a straight chuck.. Just, barely.. (I plan on doing something about that when I need to replace the tires but frankly can't afford to do that just now)
Extension lines are a good option, And I may use them, however the problem with them is that they are a very common source of leaks in tires.. This concerns me.
I do find the "Trucker" Type inflators and tire guages work very well for the outer dual.. However I"m having a bit of a time with the inner dual.. On that one I take a rod and using both hands position the guage/inflator with one hand and use the other to press on the chuck NOT in use to take the reading. That way it presses squarely onto the stem... But a larger hole in the rim.. Would be very very nice.
One option I own but have not yet attached.. Mostly because I can not, personally, do it (Hands too big) is the Crossfire tire pressure equalizer.. This system consists of two extension hoses and a "Magic Eye" type pressure guage.. I hook one hose to each tire and so long as the pressure is more than, about 70% of the "Set point" (70 PSI or 75 PSI in the case of the units I have) the pressure in the two tires is equalized.. There is also a very easy to access fill port.
Should a tire blow and the pressure drop BELOW the low-pressure limit.. The unit will close off the blown tire.
NOTE: if you add something like a dorian pressure pro to these (They come with an optional second fill/read port) The pressure pro senders may not fit on the 2nd port though, but read on)
Then one sensor can read both tires.. Here is how it works
Assuming the main port is the outer dual
Assumption2: The proper pressure is 100 PSI
Tire pressure 80PSI or up.. The pressure reading is the pressure in the tires
Tire pressure 70.. Inner dual blown
Tire pressure zero The outer dual is blown
Very fast and easy. use the 2nd port to inflate the tires so long as you have at least the minimum pressure on the outer dual.