Testors Dullcote

I have not tried decanting, but they do sell the stuff in bottles, which can then be hand brushed or thinned and airbrushed.  They also sell the lacquer glosscoat in bottles.

Back when I used Dullcoat/Glosscoat, I simply thinned with paint store lacquer thinner.  Cleaned up the AB with the same, then ran a brief squirt of mineral spirits through it.