Hodges,
The lacquer is less volatile because it does not have the VOC's required to be sprayed. The excessive VOC's of regular spray Nitro is part of what makes it so dangerous.
I use McFadden's and got it from a distributor in quart cans. I don't remember the price. Others use some off the local shelf stuff, like Parks or other brand for spraying. It works too.
The formulation for McFadden's is one of the best and has changed over the years adding more plasticizers I understand to keep from age cracking.
You might be able to take brushable lacquer and cut it with lacquer thinner and retarder and come up with a great product. Unfortunately, your guitars become the guinea pigs for your attempts at self formulation. You can always strip them and try something else, I suppose.
I went with the tried and true, just to avoid the learning curve. Sylvan has used another brand called Mohawk and swears by it. I've enjoyed spraying McFaddens but have used Parks successfully too. Good luck. This is a part of craft mastery in itself....