Well I have never had a gun with this Helice system to study. There is very obviously "NO Comparison" to any of the three I mentioned. Two of these as I stated have absolutely no adjustment for wear built in. The lever on these simply comes to a stop when it reaches the center position with the bolts engaged but not hitting a stop or taper on their own.
The third one, the Lefever, is an early pivot lever gun. This gun uses a vertical rocking bolt which engages a notch in the square shouldered Doll's Head from the rear. A screw through the top tang in front of the lever bears on the top of this bolt. Tightening it presses the bolt down thus taking up wear. The lever is closed by a spring operating on the bolt itself & the bolt is stopped in its forward motion by the lever coming to its stop. It was not made, nor ever intended, as were neither of the other two to stop short of the center position.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra