So, after all that messing around with the Candys, I passed by the bike store one day - I wasn't even planning on going in, really! - and there, on the whiteboard outside the door where they list the unadvertised sales, were Eggbeater C pedals for 1/3 off.
I figured it must be fate - I had told myself that I would try the eggbeaters if I ever found them on sale, and there they were the next day (I never did take Kim up on her kind offer for the loaner set, btw - but thanks again, Kim, for the offer!).
I wish I tried the eggbeaters from the very beginning - they worked perfectly from the get-go. I think the problem I had with one shoe with the Candys was interference of the sole of my shoe with the platform on the Candy pedal. This was remedied for the most part by messing with the position of the cleat on the sole of that shoe. But I had no such problem with the the Eggbeaters, presumably since they have no platform. Clipping in and out with either shoe is a breeze, no need for me to "fine tune" the cleat position.
Two thumbs up.
(My husband, who still likes the Candys, now has my old pair on his Bridgestone.)