measure first, shower curtains will not reach from ceiling to floor. IMO, you would be better off with a roll of 6mil or 4 mil poly. You may need a bit of light duty framing of some sort to hold it up. The 6 mil is easier to work with and last longer, but costs more. The light drop sheets that you mention might do the job as well, but do the measuring and pricing first before you assume that they will cost less. The plastic in them is a hell of a lot lighter than even the 4 mil stuff, so quite delicate.
Good luck with it.