Thanks. I already read the article, and I just took another look at it. I pass the stand-against-the-wall-and-raise-your-knee test w/ flying colors.
I can't quite get my straight leg elevated in front of me to parallel to the ground without leaning back; my quads just freak out, probably because I've haven't done any L-sits or isometric flexibility work in ages. I can swing my leg to my chest without much knee bend when I do a leg swing for a dynamic hamstring stretch, though.
If the exercises listed in the article are a sign of what you need to be strong at to activate your glutes, my glutes must be firing; my front lunge passed my back squat last Thursday.