Thanks, JimK.

I meant also to reply to your original question about a Prusik's diameter: "On Rope" suggests that the Prusik rope's diameter is about 70% that of the climbing rope. So 8mm for an 11mm rope sounds right.

I'm interested in looking at some of the polyester, as you, Nick, and BlakesHitch have discussed. I'm thinking that I'll first try a footloop Prusik of this, and then possibly try a split bridge of 0.5 inch polyester for my Blake's hitch.

For ascending SRT, I don't use prusiks, but ascenders, for ease and speed. However, if I were, I'd choose a Klemheist or Krutzklem (Hedden knot), over a trad three wrap prusik any day. Or better, try a distel, schwabisch, or even a french prusik--anything that is easier to slide after loading.