custom vex shifter enclosures

My team this year gave me the task of making a custom enclosure for the vex two speed ball shifter. We attempted to do this last year for our pto but failed to receive a critical dimension causing us to slip into neutral. We have just finished assembling our shifters this year (with the custom enclosure I made) and upon installing them, realized we’re having the same issue. The small little shaft sitting inside the shifter mechanism when the piston is retracted, is causing the ball bearings to sit just on the edge of the chamfer.

When we rotate the wheel with our hand and no pressure is in the cylinder, the shifter slips into neutral. This is not the case when the shifter is in high gear (piston extended)

This proves to us that the standoffs the piston sits on is the wrong length. Does anyone here have any ideas on how to fix this or better yet, the proper spacing between the piston and the first gear?

we ran into this problem when upgrading to a larger bore cylinder for our winch. We simply replaced the standoffs with ones that were the correct length. They are the same standoffs that come in vex kits, we used the 3" ones and cut them down to the right length and re tapped the one end.

The drawing with the dimension you need is in the following document: