I've got this small plywood circle and some tooling leather... and I note that Joe Lindsay used to make targes about that size, with either arm straps or a single handle that sticks out from the back.

Are targes in the 10 to 12-inch range at all historical?
Are either of these grips on such a small shield as good as a central grip that's in the same plane as the shield's body (as per a buckler with a boss cutout)?

I had figured that a strapped shield ought to be at least as wide as the forearm is long, and a protruding grip without an arm strap might tend to flip when struck. I've also made one with a dhal-style double grip, but it's pretty uncomfortable to hold (though that maybe partly because the grips are just thin leather straps).