I'm finally in sight of the finish for a little single-figure display piece. It's being built for a Christmas present, so I'm trying to get it right.

I'm using something called "Liquitex Gloss Heavy gel Medium", which I gathered (from this site) was the most commonly used substitute for expensive model water effects.
Problem is, I put the first application three days ago, and the thicker parts still haven't completely dried. Now, I realize that you can't slop this stuff on real thick, but the thickest places weren't even that thick, and it's been in the warmest room in the house for the last day and a half.
Right now, it looks like some gloss over the rocks, with a few milky colored areas. I'm wondering: How do you get a nice, full-bodied waterfall with this stuff, since it seems to only dry in thin amounts, so it just looks like the rocks are wet.
Normally, I'd just wait for it to dry, then keep applying more layers, but at this rate, it doesn't seem like it will work out that well.....I'll be lucky if it's done by Christmas

Any suggestions?