I am painting my 14' flatbottom DEAD GRASS GREEN and using black, brown, tan, and green all flat finish to break up the outline. You are on the right track. I will use 2 quarts on my boat, the same should work for you. I have camo'd a couple of boats like this now and they look great. All we do to hide them is throw some cut grass or reeds in the bottom and over the seats.
Watch out for the added weight the Arma (Rhino) coatings add. Remember you still have to lug around decoys, dog, & buddies.
I will start stripping my boat down and painting it after the 4th. I have a buddy who paints flames pretty good, so I might have to ghost some on.
Good luck