That sounds like a good idea if I'm reading it right. Anything that mimics the range of motion you are after will help.
For stretching your glutes you've got a few options.
You can try laying on your back with one leg bent up. Place your other foot across the bent knee (much like you have it in the chair freeze), then, placing your hands on the hamstring of your bent leg, pull it into your chest.
Another option is to have your legs in a simlar postion, but be sitting up with your hands behind you supporting your weight. If you push your butt up off the ground a bit you'll be able to find a good stretch with a bit of adjusting your position.
Hope these make sense. If not, just google glute stretches and you will come up with a lot.
I also remembered you should put some effort into stretching out your obliques, which will also help with the twisting of your torso. A good one is to lay on your stomach and push up your upper body, which will stretch out your abs. If you then go up onto your toes and bring your hips off the ground, you'll find you'll be able to twist your body and feel the stretch down either side.
Again, hope these make sense. Good luck and keep us posted on your progress!