I've seen a few of these, and am interested in trying one, but as I make sketches to figure out where the liner will go, I get a little shnookered. Is the liner simply placed between the cap course and the top standard-unit course (for Versa-Lok), with the mouth of the waterfall one course lower than the rest of the wall, liner sloped up at sides (making a bowl with the opening at the falls), and just cram silicone into the seam between the caps (where the water is spilling over) and the liner? I saw one today, and the wall was about 2' high, the mouth of the waterfall about 2' wide, but the wall had about 3-4' of horizontal area that was wet. I'd really be worried about water getting behind that wall and knocking it over come winter. Any tips?