Hi, RC - First, if it's been sitting for ten years it might well be pretty contaminated, by dust and such in the air. A good cleaning with alcohol and clean tissue would be a good prep.
Tamiya acrylics are user friendly, their X-20A or lacquer thinner work well, I also use 71% alcohol for thinning it with good results. I find it works well when thinned heavily, I start at a 50/50 paint to thinner ratio, often spraying at up to about 70 % thinner.
Testing the results before painting the subject will let you know what thinner ratio and air pressure is best. The key to all of this is lots of practice.
Shiny, non porous surfaces work better for checking spray results as you are testing, cardboard soaks the spray up a bit too fast.
The make and model of your airbrush would be good for us to know, but if you practice enough on a test surface, your results will let you know if you should do a solid color, or camo.
I use Stynylrez primer when I do prime, but I don't always find it required. A good base coat of Tamiya acrylic works well for me, but as said, a good clean surface is the first order.
Other members have good results using hardware store primers, hopefully someone familiar with them will stop by to comment.
Good luck with your project, my recommendation would be to first do lots of practice. It's an easy process when fully familiar with the details, but it does take some time and patience to learn the required steps. It sure did for me.
Please check in and let us know how you make out, or have any other questions.
Patrick