I have a glass panelled door that i stained years ago with a spirit based stain ad left it unvarnished as we liked the matt look, I would now like to paint with a Crown trade oil based that we had mixed to match the other doors and to be on the safe side should i use some Cover Stain first after a good scrub and a light sanding, I say Cover Stain as i have some and b-i-n is dear for the amount i would use.TIA.