FeatherWeights use either Singer or Tri-Flow oil. Tri-Flow is better, but there is nothing wrong with Singer oil. I use both to tell the truth.
For the gears under the thread spool cover I use Tri-Flow grease. It's great, but there is nothing wrong with using Singer lube.
For the motor, use only Singer lube that comes in the tube. Not Tri-Flow or anything else.
The qualities that make the Tri-Flow grease great for gears is the same thing that makes it unacceptable for Singer motors.
Hope that helps.
Joe