I am ordering an aimpoint 4moa w/nv to put on my bushy m4a3 rifle,,,, I have the back carry handle sight cut down to act as a cowitness, and am getting the 22m68 canteliver mount for the aimpoint,,,, my question is...............

my dealer emailed me today and asked if I needed a half spacer or a full spacer,,, and I did not know the answer,,,, to co witness the sight which one do i need,,,, thanks for your answers in advance

There are 3 spacers for the 22M68

1/2, full and cantilever.  The cantilever is the same height as the full spacer.

The full or the cantilever are what you will need for cowitness.

Your dealer is confused as to what you want.