I was always having a hard time getting each shot leveled up. Then I realized the leveling issue was caused by my standard tripod... green spirit level, handle and head. So I unscrewed the standard head and put in the spare parts drawer. 

That left a 2.5" long x 3/8" diameter shaft revealed. So I bought a standard threaded 'Union'. See white protrusion on bottom of the center of Quick leveller triangle plate.  The exposed threads were then screwed into 2.5" x 3/8" interior threaded shaft.

Below see full assembly.  Removing the bottom standard tripod head allowed only the Quick Leveler deck to be used to align the Kiwi+ pan head.