There are (at least) three ways to get a good rig control panel, and I suspect you would be best served using the second way:
Build your rig with a rigging tool like rigify that generates its own rigging panel.
Use a rigging layers management add-on like Bone Layer Manager
Write your own python script to create and manage a UI.
Bone Layer Manager is a free ...
You must have a bone for each hand. Parent your object to the armature with the With Empty Group mode, then assign the vertices of your object to the group they are supposed to be part of, decrease the Weight value along the obect:
Now when you move the hand bone, it deforms the object: