Thanks for the tip. Elected to do binder clips instead of clamps. They're cheap, and they actually fit into the channel with the J-hook of the liner, so they wedge it in more tightly.
They work way better than duct tape, which tended to let loose, and leave adhesive residue.

Using the clips, I was able to hang the liner by myself with relative ease. Left the clips on until the water was starting to flow into the skimmer. Filled it with a garden hose, so it took quite a while to get there. Took the clips off with lots of apprehension, but the liner has stayed up. Thanks.