A rail mounted matte cutter will give more consistently professional cuts than a free-hand Dexter with a straight edge. I would also frame with a metal frame such as the Nielsen frames and definitely under glass. Use archival board and over matte with 4ply or 8ply board. I only dry mount when necessary (now) using archival corners because if a purchaser wants to re-frame to a different size an accidentally miss cut matte could ruin a print. Also humidity stains on a matte especially in a location you don't control would be a problem.
Remember you are presenting your art and "good enough" is not what sells.