[sourdough]

This won't answer any of your questions but why would you want to go to the expense and trouble of putting this on?

I have a 14 Cougar High Country and it has the enclosed tanks in front. I leave both tanks on and about every 3 days pull the 2 rubber straps that hold it closed, lower it just a bit and see if the regulator shows red. If so, off comes the cowl and out comes the bottle for refill. Really simple and easy. With 2 bottles I've never found that I need to know if one is "partially" full or not - just run it till it's empty and fill it up.