Hi,
The TRIAD should be a very good fit no wobble, tru-running spur. I have installed it on C4.1 / B4.1(2) / B44.1 / B44.2
The black top hat spacer should key fit into the slipper plate.
The black top hat spacer should sit flush where the ground flat part of the top shaft ends.
Something like this:
The image above is for the C4.1, to get the top hat spacer in the correct position (C4.1 motor plate is spaced out) requires shims between the top hat spacer and bearing.
Contact me if you are not happy with the installation.
MiCk B. :-)