In the video I'm practicing Bharadwajasana ashtanga style, here in Vinyasa Krama we look over the shoulder on the same side as the folded back leg.
The unbound hand rests on your hip rather than placed under the knee....firmly if you need the extra support for the twist.
Try to keep the shoulders level, there's a tendency to dip the side your twisting in to.
Twist a little further whith each exhalation
Mahabandha (pic 3) engages five bandhas or locks
1. Maha bhandha : closing anus with heel
2. Mula bandha : rectal lock
3. Uddiyana bandha : abdominal lock
4. Jalandhara bandha : chin lock
5. Jihva bandha toungue lock