It sounds like your wallsits are like ball squats against a wall. Are they? Sounds like you had a good workout - are you increasing weights with each strength workout? What are your sets/reps like?
That's one thing I can say about NROL, its full body workouts are indeed full body - and with an economical 6 exercises per workout.
The wallsits are just with my back at the wall and my legs like im sitting flat on a chair, holding for 1 minute x 3 sets. I havent increased the wieghts yet as I'm still going through my first week but I will.
Hope you're having a great day!