If you sand off the glass, try to remember what grit you used on your final sanding originally because that will determine the color or darkness it wets out. If you use too coarse a grit compared to what you used before, it will be a dark blotch on the deck. If anything error on the side of smooth when you get down to bare wood. It's not easy to match that darkness since so many variables determine the wet out color like temp, viscosity of the epoxy and the surface texture.