Ooh, actually the bulk cable I bought does offer plenty of other length options. Pricing isn't terrible. ~$0.26/ft for 100'. I got 300' at $0.21.
And from what I could tell, Riser rated is fine for short-run home installs (~50ft). No need to spend more for Plenum, ya?
I might need to run some lines through a short vent duct section, but even for that I'm skeptical that plenum matters. Although... only a $10 diff for the length I'd need in the ducting... 🤔🤷♂️
https://a.co/d/3RaZTBh