Just getting in to the hobby myself so don't know jack about the building aspects of your question but I am knowledgable about paint having sold it. I see no reason why you can't use a good acrylic spray can paint. You will sacrifice some durablity and looks but I see that as the only real negative aspects to your idea. I remember when I sold paint how many people would come in and complain about Wagner Power Sprayers that they bought somewhere else (also Thompson's Water Seal-both junk products). We were always fixing problems from the mass merchandisers, people when they get into trouble go to an actual paint supply store to get bailed out. If you ever saw a cheap/small Wagner Power Sprayer you'd wonder what made someone think they could paint a big house with it. But, in this particular case something like that might work for your application since it is small. You could probably find something for about $100-$150 that will do a decent job and perhaps the savings of not buying aerosol form paint may recoup your intial expense. Something to think about.