VC17 is fine for fresh water. The advantage is that it is easy to prep from year to year. I guess its not uncommon to go 2 years between paintings, but I would think that being out of the water between seasons would reduce the effectiveness of the product. Unfortunately, the stuff gets more expensive every year. Fortunately, I can cover the bottom with a little less than 3 quarts. I still choose do do mine annually at least until I have to get a mortgage to buy bottom paint.
My concern is that I may be moving my boat to Chesapeake Bay. That will bring a whole new set of issues into the equation. Might be a total bottom strip job. I never investigated whether VC Offshore could be applied directly over VC17. (That would be too easy...)
I agree with the fact that the material will evaporate unbelieveably fast is warm, breezy conditions. I do use a narrow roller and a small roller pan and I keep the pan covered loosely with foil to prevent evaporation. Others are very successful using the paint in a ketchup dispenser, squirting small amounts directly onto the roller.