I prefer center-grip punch shields over enarms. You lose a bit of stability for bashing, but the shield is more maneuverable and versatile that way. One of my favorite techniques is a stiff thrust to the outside corner of the opponent's shield to pop it open and hook the inside corner with my own shield to pry it open. When I'm finished with the first part the face of my shield is to my outside, at which point I then cross my sword under my shield to deliver a cut to my opponent's sword-side shoulder while I have him open. The ending position is essentially what you have cutting behind your buckler from crutch in I.33.
As a general critique, not enough shield work. There were a couple opportunities for an edge check or bash that were missed. Against the two-hander you should have voided the leg then pressed hard with the shield to tie her up.