Thanks for this reference Mark.
I found some videos of him demoing his "Big 3". I'm already doing something similar to the Bird Dog, but I think I like the BD better. Will discuss with PT tomorrow. I've been doing what I consider his "Curl Ups On Steroids" for a while now... I'll probably keep doing mine, but will add some of his just to see. His version may be better for back alignment (on the floor vs on an exercise ball) but my PT version is way more core intensive. I got the "no more sit-ups for you EVER" talk from PT early on. I've got better abs now than I've had in 20 years, with zero sit ups. I really like his side planks! What I've been doing for that has seen mixed results... Will talk with PT about switching.
If I find these working well I'll probably order the book with videos. Something about reading books doesn't convey the details for me as well as video.
Another few tools in the tool bag.
ETA: This was a good demo video. Not McGill, but his student/client.