Guys, I've tried the single loop situation in my yard using 8 mil rope and I must say it's very uncomfortable as some have pointed out. However, if your life was at stake, and with adrenalin running high, it might be a different story perhaps.
Nonetheless, we will abandon the single loop exercise because SS369 threw a spanner in the works when he posited the loose boulder falling and rendering my poor twin brother unconscious scenario.
Therefore, two loops or three loops now seems to be the choice, nobody present has a backpack or similar so the successful rescue has to depend on the rope alone.
So, what method to use? The Karash Double loop? the triple bowline? Some combination, that once in position, will allow him to be be hauled to safety, conscious or unconscious.
And remember, it must be tied/preassembled by me, at the top of the cliff.
I'm depending on you, my learned friends, to point me in the right direction!