After some adjustments, so good!

But in fact I found having a handle on the back of my hand very unpleasant, it blocks me, I can not start easily! Between the rest position (when I wear just the unit swinging arm) and the target I have to reposition my hand, very unpleasant!
Pus like other have said the screw carrier has no bearing, rotates, bends, short it sucks ...

But in the end with a few tweaks, I arrived at a solution that suits me: I cut the part of the back of the hand to remove the clip and strap, I tied the female clip on the strap, and I kept the clamp wrist. So actually I end up with a kind of strap and more sophisticated: a fastener very solid and comfortable wrist that filled his role well in case of device loss (if I loose inadvertently), and stays detachable thanks to the clip! it's great :)