I'm 9 hours into the "timed sock," and I've just set up the ribbing for the cuff. Progress will be slower from this point on, as K2P2 ribbing just takes longer for me.
I still did the heels one-at-a-time on these socks, but I didn't move them to separate sets of needles -- just let one sock flop there while I worked on the other one. Didn't care for it. It wasn't excessively awkward, but it puts too much weight on the working sock, stretching the stitches where the heel joins at the ankle even more than usual.