Length and diameter of Prusiks loops to ascend the Half Dome cables?

Hi everyone,

I'm going up Half Dome with a group in mid-October right after the cables come down. We are going to be using the dual prusik loop + carabiners + harness method for ascending the cables. I’m getting some conflicting information about the diameter of the cables, though, and therefore am a little unsure what diameter of cord to purchase to make the Prusik loops.

If anyone can share the diameter of the cord they used, the length of their Prusik loops, and/or what diameter they remember the cables being, I’d greatly appreciate it. This is the information that I’m going off of for now:

• The cables are about 20 mm in diameter (this is based on a few forum comments I’ve found—I am not 100% sure).
• Use 7 or 8 mm cordelette for the Prusik loops? I thought the diameter of Prusik loops should be about 2/3 of the diameter of the main rope, but it seems that would require a super thick cordelette, which I don’t see people mentioning.
• Have each loop be about 20 inches long (folded length, not circumference).

Thanks!