Awesome video Kick!
It does bring a couple things to mind. I think keeping the shield in front of you will not just decrease the power of the throw, but also change the usual point of release. This all occurring because the shoulder on your shield side will need to stay in the same place (more or less), preventing the upper body from rotating.
Also love that setting. The background in your video looks so clear and pretty, if someone told me it was fake and you recorded in front of a green screen, I would believe them.
And the big question. With that buckler in hand, would you move to the other side of the field and let someone sling tennis balls at you?