I've already stated my preference for fresh grease in the bearings and a light coating of heavier, sticky oil. But, there are
other things you can do to make a vintage SA hub run and shift smoothly.
First, a new chain. It's amazing how much a new chain can quiet down the drive train.
Second, you can experiment with cog alignment using the ring spacers.
For shifting, check that the indicator spindle chain is straight and supple. They can be damaged from the bike falling on the right side. A rusty, sticky link can make shifting dodgy. Also, the chain should not be screwed in fully. It should be backed off one turn so the links will self level against the nut. And , of course, a slick, smooth cable. New is always nice.