Brilliant, thanks PanRonnie

Its just a super lightweight one piece adapter and not rocket science.
The only question it raises is whether to vent/ drain the dump cavity to atmosphere as the photo shows(into the leg) or vent/ balance the cooling system back down through the main water infeed gallery as is done with a two piece adapter the answer to that question simply determines the position of that 1/8 hole in the pan plate.
The hole as shown in the specs you've posted will increase water flow though the motor as it vents continuously to atmosphere whereas the equivalent hole in the 2 piece system doesn't promote flow because it is a port with approx equal pressure at both ends.
My idea might be to do the 2 piece equivalent first using just the hole into the water duct then if that doesn't work drill a random 1/8 hole as in the pic.
Im trying to work out the engineers thinking was and it may be to do with the gasket.
That 1/8 hole is through an existing hole in a stock gasket.
If the hole was put in the center into the main infeed water gallery to mimic the 2 piece it would require a modified gasket which would lead to many disasters down the track.