That’s great! Thanks for sharing.
I’ve been experimenting with advanced versions of two of these exercises. The Curl-Up can be modified by lifting your elbows off the ground with your shoulders. This is actually recommended by Dr. McGill.
The Bird Dog can be modified by putting your weight on your toes (instead of your knees) with your legs out straight (so you start in a plank position from hands and feet). Then extend your arm and leg as before. The next step is to start from your elbows and toes. I haven’t read any studies done with this form of the exercise, but it is much tougher so be careful.
If you practice the original form of exercises regularly enough, you may want to step up the advanced version. But you can always fall back to the basic form a good maintenance exercise.