this is a recurring issue, maybe time to put it in the technical section. :thinking_face:
I use a simple bar of aluminuim placed as in the picture (turn around to tighten/ loosen the cush nut). No need to lock the rear brake or stuff string in the cylinder.

email (option): petercomley@web.de

here's another picture of the setup

email (option): petercomley@web.de