also when doing an atmospheric nitromethane disstalation do i just use a regular vacuum adapter with no vacuum or just a bent adapter
Either will work, but I think a plain bent adapter is preferable.
when putting a disstalation setup together, what is best to use. Vaseoline or silicone grease? The grease is that the kind you buy in the automotive section?
High temp silicone would be better than vasaline. Use the smallest amount of grease possible, its only to prvent your glassware from sticking together, you don't want it to contaminate your product. Apply it, then wipe off any excess with a paper towel.