https://oldsingersewingmachineblog.c...-two/#comments
this posting gave me the most help in reassembling. The singer 201-2 tension has the most similarity to my Standard Rotary. There is no felt pad in that tension assembly, so I put it between the second tension disk and the outer cover. I don't really think it is having any effect there, but I'm not taking it apart again! The inner spring has a terminal spring hook that appears to have to fit in a cog that is just visible on the inside of the machine. I could not get the spring loop to be springy until I assembled with the loop hanging down and had someone hold the spring inside the face with a screwdriver while I jiggle the outer assembly onto the tension stud. I also realized the tension stud has a release pin inside just like the 201-2! Here is a picture after the final reassembly
[ATTACH=CONFIG]564624[/ATTACH]
here is the tension release pin from the outside
[ATTACH=CONFIG]564625[/ATTACH]
and inside- red arrow indicates lever that connects release pin to presser foot bar.
[ATTACH=CONFIG]564626[/ATTACH]
I don't think the tension release works exactly right, but good enough! It is stitching lovely (with a little help adjusting timing by local Old Sewing Machine Guy at Auburn Sew and Vac. Hope this might help someone who is trying to find info on this machine in the future.