Pocket Watch Waistcoat

What would you wear?
I recently acquired 3 waistcoats (vests if you perfer). All three are single breasted with pockets on the waist.
~ black with white pin stripes, satin backing
~ (slate?)grey
~ grey/beige thin plaid (?) with some red crossing.
I got the idea to wear them from watching old movies where a three piece suit was a must. I wanted to know the best way to go about wearing them in a casual yet classy manner.
Pictures would be helpful.
Thanks ^_^
I suggest you buy Mens Vogue and take a shopping trip down Madison avenue in New York for some fresh ideas.
Alice In Wonderland (1903)