Measuring TC input gear

A bud in the NAC hooked me up with a few 23 spline input gears to swap into my rebuilt 242 for the new rig, i'd like to swap this in and return the one i dont need.

I need to verify the length of these before i do so, i need an .0840" 23 spline input. At what point do i measure from? Seal, c-clip or bearing face to end of input?

Thanks..

See if this helps:

http://www.novak-adapt.com/knowledge/np_nvg_input_gears.htm