As someone who's sewn waterproof/repellent fabrics for lotsa years - I did not like the way my 01's top was acting like a sponge. They're usually three layer'd, so it's not like my toupe was going to get wet, but bird s__t would stain and I simply prefer water running off the back. The first thing I did was mask if off. You can smell the solvent carrier and besides it's easier to prevent a problem than mop one up..
I was going to do the whole 14oz (397g) can, but still have about a third left after three pretty heavy applications. We got up to a whole 65f. today, so I'm not sure it was drying as well as I'd like - I didn't force the issue. I'd not suggest you rush it with a heatgun but perhaps a hairdryer would help a bit - if you don't have anything better to do. Anyway - it seems to work and I'll keep a log to see how long it beads water...
Cheers..
jim