Everyone has their way and their opinion, as that's what works best for them.
Here's my 
solution to the problem of checking and filling the inner dual.  I also added a short extender neck to the outer dual.  
I was my opinion when I first got a unit with duals that it would be easier to check the outer dual than the inner - I found I could reach in and check the inner with the long gauge, but the inner was darn near impossible.  Opinion changed!  
Having the long tire valves in the inner certainly helps, but I also like to rotate my tires so I'd have to have the long inner swapped every time.  I'd much rather do what I'm doing.