Use Photo-Flo (or the Arista, etc. version) unless it's specifically indicated NOT TO USE by the manufacturer of the other chemicals. For example, I think those C41 development kits require you to make the final wash the stabilizer wash, or else your negatives will start to look funny after a few months.

I hang film in my shower as well, never had a problem with spotting when using Photo-Flo. I dump the solution right into the open developing tank and carry it into my bathroom. I gently remove the film from the reels, dunk it in the solution, and pull it out from one end slowly and then hang the film from that starting end. This gives a bit of "wicking" action that takes off most of the solution anyhow, and I've never needed to squeegee.