I have only tried both denatured alcohol and 91% Isopropyl and have good success with both for sealing. If you had to purchase something I would go with the denatured alcohol to be safe. I will say that Alcohol doesn't seam to have any ill effects to Z-Poxy Finishing Resin (what Greg uses in his video).
Yesterday, I layed up some 5 oz fiberglass cloth to repair a cowling using the 91% and Z-Poxy FINISHING RESIN. I think Greg uses a 1:1 ratio for the 1 oz cloth he uses in the video, but for thicker cloth I used the resin needs to be a bit thicker. Thinning this particular resin doesn't seem to make the cure time longer....about 3 to 4 hours.
I haven't tried acetone,lacquer thinner, or xylene but may try it in the future. Like I mentioned earlier, experiment with whatever you have first before you risk ruining your project!