In reply to colin8ll:
id go for a standard bowline tied with the bight of rope (triple bowline?) with a yosemite finish.
bowlines dont take well to abnormal loading (loading the loop in multiple directions) so best not to build an anchor/belay off your tie in loop. but you could build your anchor off the bight formed by the yosemite.
im not sure how the yosemit bight would take abnormal loading or being pulled in the opposite direction to the standing parts (bringing up the second without redirect).
anyone got any handy tricks for differentiating between the left and right rope. i was considering different coloured electrical tape at the "ends of either strand" and each side of the belay device, this will be reversed if bringing up the second of the anchor in plaquette mode.k