All that is left to do is to mark the hand grip position. Have them raise or lower the shield until the top edge is where you can just see over the top edge. Mark on each side of your clenched fist. This is the position and angle for the handle. If the knuckles of your hand touch the shield when you are holding the hand grip, you will loose both your grip and control of your shield.
Opponents love to face fighters who loose control of their shields.
Besides it can be quite painful. This guard is bolted down over the handgrip in a position that covers all the hand. When holding the shield be sure that you do not let your thumb or fingers stick up through the wire guard. Last, but not least, the strap that holds your forearm in place. Two schools of thought govern this subject.