Unless you are stringing gut not very. The Wise had a problem with gut initially. The tension head was below the level of the string bed pulling on a plan parallel with the string bed. When the gripper pulled tension the string angle going into the gripper changed and the front of the linear gripper damaged the string so Wise came up with the spacer. The Spacer stops the 360 rotation so Wise came up with a diablo.
If you are using string that is not damaged with the Wise without the diablo take it off. Be mindful when you start using multis and gut though.
I would like to apologize to anyone I have not offended. Please be patient I will get to you shortly.