I bought paint remover and completely stripped a 14 foot aluminum boat. I went to a boat dealer and bought a can of aluminum oxide primer which can be used sparingly. Then I bought my paint (KRYLON)) in rattle cans from Menards, masked the boat off and sprayed it. It came out great.
If you need just a little then buy aluminum primer spay can from nearest marina (about $18).
Did you ever think about using camo cover that peels off and sticks???Cabelas carries it when you figure cost paint and time I am trying this.