A Roman Walk In The Park

[Neuraleanus]

Surely you just need one strap? It goes around the handle then over your left shoulder. You keep your hand around the handle but your shoulder takes the weight. Then if the shield was needed quickly you just grip the handle and you can lift it into position. If need be it can be looped over the right should to move it behind you.
The above one just looks like there's more bits to break.

The problem with a single strap is that your legs tend to hit the shield. With two straps, one strap goes around the right shoulder moving the shield to across the your back. You can then balance your kit hanging from the furca pole across it and the combination becomes very comfortable.