I gelled up to areas where I then carpeted. The wax additive worked killer... it kept the air from the top layer making a solid hard finish easy to sand or whatever. I use the additive with my resin or a piece of wax paper for small repairs with same results. Resin or gel needs to be protected from the oxygen for complete top dry. Haven't tried your method but it has to be some sort of wax additive... Prep consisted of a good cleaning then light sand, wash/wipe down. Dont do any repairs with epoxy as the gel wont dry over it. Marglass is quick and drys fast for small non structural areas. The hardest part was timing the amount to use/vrs dry time. I used about a half qt of gel at a time doing sections in that order.