Most Jet-Vdrive guys with big cams are using a Banderlog valve to turn the water on and off. http://www.banderlog.com/products/waterInjectionValve/waterInjection.html
I never dry the tanks. It still has fuel in the tanks from last season. Never had one problem with water. You guys are missing out on a great fuel. I went from 94 unleaded 1to1 on the blower to e85 and 23% over. Here one more E85 boat for you guys. Twin turbo 540 and 20# boost...
That could be it. I'm there every year. I didn't run the hydro much this year. I was having to much fun riding shotgun in the pink&white HTM and the 25 Warlock.
The closest I've been to NW is when I went to Gun Lake this summer. Maybe I've seen one of your advertisements. I just know I've seen that sign somewhere before.