I find that most of my plastic bottles & jugs (indented groove or not) end up being single-use as winter sowing containers. The plastic often gets brittle after a season out in the sun. When I'm done with the container, I just put it in the recycling bin (where it would have gone in the first place if it hadn't been re-used for plants). I often cut my containers not-quite-around so there's a "hinge" between top & bottom... when I'm hardening off plants, that hinge gets cut, and i've found it's easier to use a new container after that if I need it to have a top. Old ones do get pressed into use for up-potting smaller seedlings or HOS before they get planted out.
I hope you won't need anything quite as complex as your described system above for getting your WS plants out of their containers!
