I tested how the hand performed at gripping and holding different objects.
Fist tests was with a tennis ball. This was the object that gave me the most trouble when it came to gripping it. I got the hand to grab the ball by placing it between the index and the thumb before flexing the fingers.
After that I tried with a coffee mug. With the mug it worked perfectly.
After that I tried with a bottle of pills. There was no problem when grabbing it, but there was some problems when it came to keeping the hold on the object. When the hand was rotated, the bottle would some times slip away.
After that I tried with a bottle of mustard sauce. Gripping the bottle was not a problem, but when the hand is lifted, most of the times it falls due to its weight.
After that I tried to improve the grip of the hand with pieces of rubber.
The increased friction did not help with the bottle of mustard, but it did help with the bottle of pills.
After this I tried with a brick of ground coffee. Gripping was okay, but most often than not the brick slipped away from the hand.
I then tried with scissors, and unsurprisingly It worked flawlessly. This should be true for most objects with some kind of handle.
I then tried with a bottle of gel cyanoacrylate and it kept hold of it every time I tested it.