EDIT 9/15/17 Changed the cutouts on the gauntlet to be horizontal to help get a better fit while wearing. Unless you can bridge 22mm, you will need to use supports.
EDIT 9/13/17: Changed the 'hand' portion to be a little thicker for a true 1/2" screw to be sunk in and also put a ramp in the back of the hand when transitioning back into the gauntlet.
This is a new design that I have been working on. It can be used to hold pretty much anything in place. It was originally designed for a stroke victim with limited wrist/hand strength. This would offload all of the weight onto the elbow, and still allow the user to assist in grasping the items. It is worn on the under side of the wrist and the curved portion fits into the palm. It uses a velcro strap to hold things in place.
I print the gaunlet in TPU to get it to fit perfectly around the wrist/forearm. Use screws to attach the two pieces and then cover the screw heads with some craft foam so it doesn't cut into their wrist.
I will look into designing a one piece design for thermoforming.
Supports will be needed with the new gauntlet design
Just attach the two pieces with screws, I used 1/2" screws for mine. Cover the screw heads with a strip of craft foam for comfort. You will need a piece of velcro to run through the hand portion to keep the items in place.