Painting the outside windows again and would like to know what others find a good paint to use. The last time they were painted l used dulex flexible undercoat and gloss but l thought it was hard to paint with, to thick and not running freely through the brush. Since it's got a gloss finish on it already does it need a good rub down before applying a undercoat this time and what about water based exterior paints any good ones l could try.....