Even a respirator is not enough protection from isocynates. This stuff is absorbed through the skin and eyes and while not using it every day for 8 hours at a time, may seem insignificant, you never really know what your bodies limitations are. If you are spraying in an enclosed area as you probably are since with the high cost of the paint you won't want the wind blowing dirt into it, you need a supplied air respirator, spray booth, or some strong homemade ventilation.
When I worked as painter in the body shop about 10 years ago and basecoat/clearcoat was the new paint even wearing a respirator didn't help. When I would get home at night I could taste the paint in my mouth as it was absorbed into the skin.
As for rustoleum, it may not be the highest quality paint available but if you thin it with acetone it will spray nice and lay flat with a high gloss. It takes overnight to dry hard enough to reassemble but it's cheaper and safer. You could also use a heat lamp to speed up the dry time. The Home Depot now has custom mixed rustoleum in over 100 colors.
If someone had told me when I was painting cars to use rustoleum, I would have said no it's crap. But actually it works well providing you prep and prime correctly. The cost is much less also compared with any automotive products.