What's the best way to lube the focusing rails on a Super D? Should I just extend the rails as far as possible and apply something to them like that, or do I need to take it apart?

If so, how do I start, and are there any springs that might fly out or any other gotchas?

Thanks for any help...

Try cleaning the rail and standard gears with a degreaser (non proteleum) then apply a very light coat of white lithium grease and wipe off excess to leave a just detectable film on them.

Thanks - smooth as butter now!