@paula We previously were designing our own system, However our laser manufacture were also developing a integrated solution.
Sadly it is not backwards compatible with the Mk4 tubes, but all Mk5 tubes and future tubes (when replacing ones in the mk4) will support it.
Its quite simple to install, simply cut the black heat shrink off, carefully unscrew the heat shrink and screw on the beam combiner in its place,
Its fairly well aligned however it does require some adjustments. We will create a guide after the next batch of machines are delivered. If you built the FabKit this should be childs play