Delicious salad! I served it to 7 light eaters and was glad I only used 2 heads.......three is a lot of lettuce! Accordingly, I used less shallot, but still felt it needed more white wine vinegar. Next time, I would use walnuts instead of pecans just because of personal preference. Typical of salads like this, the oranges and nuts tend to sink to the bottom of the salad bowl when tossed, but it was quite good and I would definitely serve it again!
I took this to Thanksgiving dinner and left the orange slices at home. Everyone still loved it. I tried it again tonight with the oranges and it was wonderful.