I would problbly use 45 mil or heavier pond liner.
Yeah I would go with the pond liner vs. Visqueen as I've used visqueen and not only does it break down it is easily punctured while you're working with it.
I used it from a Greenhouse supply company (best way to order it and cheaper too) to line a small 25 by 25 pond. I was great until I dropped in the aerator and popped a hole in it. I put a layer over it again and put trout in it that were moved from the 1/10th acre pond. They got really stressed for some reason.