I've been using the preval sprayers for quite some time when I use Dura Coat products for gun refinishing. They are a handy little unit that comes with a glass jar and if you clean the jar out with paint thinner or acetone you can reuse them over and over again. I get quite a bit of life out of one spray cannister of propellant. And yes, you need to do this in your garage or somewhere other than the house. Any finish you use has chemicals in it that are toxic, but the sprayer propellant itself has no odor.
One question, does Thunderbird finish have to be wet sanded or is that just an option up to the person finishing the bow?