I'd use the 1.4 for a sealer. If it is an actual product that is sold as just a sealer, then activate and reduce also if it says to in the tech sheets. If you are using an epoxy primer or urethane primer as a sealer, then again look in the tech sheets for how to mix to spray as a sealer. It would be reduced more if used a non sanding sealer then if you were using it as a primer to give fill and sanding itafterwards. The object is to get the sealer to lay out flat so you can spray your base and clear after allowing proper flash time, without sanding in between. You could always sand, but if you lay it out good, no reason to if you don't get past the time window allowed to spray your base coat on. Reading more now what you posted. If your 2k primer is a color that will cover well with your base, I'd skip using that sealer. It sounds like a 1k unactivated sealer from what you have posted. Is there not an activator. I see no advantage to using it if you are spraying the entire truck with 2k primer and sanding smooth, final sanding that with between 400-600 wet. That sealer may cause more problems then good. If it is unactivated, take it back and ask your paint supplier why he is selling you crap 1k sealer when you have it all in 2k primer. If it were an epoxy product, it would be different. Wtf? synthetic enamel, geez.