AusTXHiker, I'm curious as to the destinations you have been trying to get award tickets to on CO. I have only claimed a few CO award tickets and those have been domestic coach at the standard level (the off-peak awards were only recently implemented). I had no problems getting the flight dates/times I wanted on CO, even when booking only 2-3 months in advance.

One thing that your post correctly highlights is that the % of seats used for awards on each airline does not include anything related to whether those award seats were claimed using standard or full (i.e., EasyPass for CO) mileage. So, while DL lags CO in overall % of seats used for award travel, it may be the case that overall average mileage redemption for similar tickets was higher on CO. This would be useful information to know, but I doubt we'll ever see the airlines break out the data that way.