SRAM PG-1130 cassette manual? Meaning of numbers on spacers that go between sprockets?
Just a guess, but does it align to the number of teeth difference from cog to cog?

That could be approximately correct except for the 36-42.

No, you don't grease the spacers, they are plastic so the will not corrode and seize to any other part.

The spacers will all be the same thickness for any number of cogs (6/7/8/9/10/11/12) as it aligns to the amount the derailleur moves per click.

Using any spacer that varies at all for that number of cogs will result in really poor shifting