I have a spare RD6 sheath waiting for my Hook - what do you need to mod so that it works?
My Guard fit fine in my RD6 sheath, only minor problem was that the plastic insert inside the sheath was closed up a little too tight for the Guard and wanted to come out of the sheath when I drew the knife. I used a little hot glue and glued the insert inside the sheath and now it's fine.