Hey all,
I use a custom made Suicide Leash. I used a sheathed 16mm sheet rope and then removed the core which left only the braided outer sheath. I bowlined it to a quick release on the harness end and a snap shackle on the other end. It is attached to a running line from one side of the back of the harny to the other. It is super strong and because it has no core it lays flat and doesn't hurt when wrapped around a body part.
I've had it for years and it works a treat, guaranteed stronger than any production leash from any company and only cost about $50 mainly from the clips and snap shackles. Go into a yachting shop (chandlery) like Whitfords and hunt around for bits and make your own.

Good winds,