Has anyone used ISC D2 Escape descender (https://www.iscwales.com/Products/descenders/RP860-D2-Escape-Descender) on Oplux? It is specifically for 8mm rope. Doesnt look like it can be installed mid-line, but needs to have the end of the rope fed through. Is that correct? Specifically looking at this or Safeguard. Thoughts or opinions? Thanks!