Its still a bad idea to breathe the water based paint while spraying because breathing any particulate can cause lung problems later on, even just saw dust. However, a decent VOC mask is safe with the water based base coat. The top coat is probably nastier with some isocyanates in the hardener.
I have been wanting to try some of that stuff too. I may paint my rototiller and see how it holds up but I have several other projects I need to do first.
If you try it, a report would be really nice!