Can I use helper bags to level out rear?

[coater]

I'm going to lower my '85 5" in front and 5" in rear,but what I have seen with this stance is the front is alittle higher,but had plan on using helper bags anyway when I pull my boat. Can these bags be used to level out the stance?
Is it possible to run a single air valve below rear bumper to air up both at the same time? Can anyone direct me to some trucks with a 5/5 drop?

Thanks for the help!
Coater