Hanging + Other Length Routines (BAD)
Don't do it. Hanging alone is intense enough.
Some veteran hangers add a light ADS to prevent turtling, but split sets are more effective anyway, so I would just advise split sets instead. Today I saw an injury from a guy trying to combine extender use with hanging. Due to this & other experiments, I can't advise anyone to ever try combining hanging with anything else. I have also tried adding edging or other 'light' work to my routine, and it backfires every time.
In the end what you do is your choice. However, Bib managed to achieve 4.5" of BPEL gains with just hanging, and many guys have gained 2" to 3" BPEL with just hanging. I hope to achieve similar gains one day myself. Personally, I wont be combining hanging with anything else.