I need a transparent, pourable topcoat to seal collage. I would like the sealer to be very durable when dry because I don’t use glass. I use canvas and heavy watercolor paper for my surfaces, and some of my objects are very raised off the canvas. I would prefer to stick with Golden. Every Golden medium and gel product I have tried has been amazing. There are soooooooo many. I see they offer a pourable matte medium. What should I use? Thanks.