Well, I do mix brands too. Mainly because there are certain products from various manufacturers that I prefer... I suppose it would be better to use everything from one line, or at least it would make the rep a lot happier, huh? I always use a good sealer before paint, who makes the Quickseal you refer to? Might have to give it a try. Without a quality sealer, bleed thru will ruin whatever paint you use....