Don't use anything but the best oil on this model. It should in theory be very easy to clean it up, but if grease or bad quality oil has been used it can need a bit of cleaning. The only thing that tends to stick a bit on these is the cam stack and parts on connection with the stitch selection. It's all about cleaning and oiling, have the machine on a table in a heated room, test sew, clean and oil.
You seem to have sorted it out very well. Rememer to have the top of the freearm off, it leaves space to clean around feed dogs and there a few oil points. The paint on these scrates easily, so remove presser foot and needle befor you attempt to pop up the top of the free arm. It's one of the most sought after vintage zigzaggers, and it's not often it comes for free.