I used the plans for Christmas 2007, modifying by taking out what I didn't want to do. Two weeks ago, I started off using the plan on a Wed., but after an hour or so realized that I didn't really need to...many of the attractions were not nearly as crowded as they had been. Most were walk on (I could see the ride vehicles from the end of the line).

The UG does say for days of "lighter" attendance, the plans really aren't necessary. I still kind of follow them anyway, so I have a plan of attack.
For my Christmas trip, I did do a lot of EMH mornings, as I am an early riser. The parks opened as early as 7, and most people did not enter the parks until late morning. I was done by noon as they were walking in, looking at their maps, and deciding which line to stand in for an hour and a half.

This year, I did not do a lot of EMH mornings. I looked at the park recommendations on the website and went off of those to make my schedule. I also tried the strategy of going to the park that had the evening EMH hours the night before too. I can't really say for sure there was a huge difference. I would probably go back to doing EMH mornings again, just because I am up so early!
I do like the UG plans. They do work. Just adjust them to your situation.