in the end i used about 3 gallons of the zavlar. I didn't paint the inside of the tank itself with anything else. The zavlar never fully cures so it'll always be a little tacky even throught the KF i painted over it with. In the end i ran a bead of silicone around the top edge to prevent the lid from sticking to the tank. Once it's submerged you are not going to have any issues with it, at least i don't. It does turn a brownish color right away tho where it is in contact with water. As far as coats i just kept painting until i got sick of it. Make sure the stuff is well cured tho before you apply another layer or you'll have issues with air bubbles. Ifyou have access to an air compressor I think I'd try applying it with a shutz gun. It is about the same consistancy as asphalt undercoating so it should spray well.