I've found this workflow works with CC3/4 characters with the following steps as in the videos:
Copy control Rig
Rename
Assign new character
Open RIg
Disconect Forward solve node
Bring it down near de Backward solve node
Disconect the backward solve node
Conect Forward solve node to the imput where the backward solve was
(The Rig should now reset its position to match the skeletal hierarchy)
COMPILE&SAVE (I was probably missing this step before)
Go to the left pannel: Rig hierarchy
Inthe search bar, search for CTRL
Select all ctrl bones (using shift is fine)
Right click: Set initial offset / Transform from current
COMPILE&SAVE
Reconect the backwards and forwards solve nodes to their places
(The finger controls become not visible anymore, I don't know why, but they really are there and can even be modified in sequencer. Nevertheless this is harder without being able to see the finger rigs.)