What should be used on the guide rails to lube them ?
They really don’t need lubing. They do need to be cleaned every once in awhile. Dust and smoke particles can build up and cause skipping. I wipe mine with isopropyl alcohol.
Jim is right. If you lube them, they will attract dirt and wear rapidly.
You can use a dry lubricant. 3-in-one make one and so do a bunch of others.