Oil in Lofrans Tigres windlass motor

[nmccubbin]

After the issues mentioned in my post a year or so, I bought a new motor from Lofrans, and lugged it with me to Hiva Oa in French Polynesia.
Motor performance has been deteriorating since installation in December. today it quit at Tauna in the Gambiers .
We opened the motor up and found at least a quarter litre of oil in it, VERY well distributed.
We cleaned it up with diesel, and are letting it dry out overnight before reassembly and test
The commutator is badly pitted, presumably because of the oil. We sanded it fairly clean with 220 grit.

Any advice on what to do before reassembly?

One design weakness is that if the oil in the gearcase leaks, it goes to the motor. We cut grooves in the adapter plate between the motor and gearcase so that oil passing the seal will drip on deck instead of into the motor.
Plan to drill a drain in the bottom of the motor casing too
Comments please on our modifications

We cannot find a way to be sure the correct amount of oil is in the gearbox. The sight glass is too dirty, and a dipstick does not work. We probably had too much oil in it.
Any solutions ??