I found a local thrift store that has a large selection of waistcoats/vests, and I'm thinking of going to get one to wear with my kilt. My question is, what color should I get? The two kilts I plan on wearing it with are Black Watch and Campbell of Argyll. Should I go with a dark blue or black waistcoat?

Also, I have an outfit in mind... I'm planning on wearing the waistcoat with the kilt (obviously), a white shirt (with the sleeves rolled up to the elbows when appropriate), possibly a tie, boots, and a scally cap/flat cap- sort of an old-school "working class immigrant" look... casual, but classy enough that I could get away with it at church or at a wedding... any suggestions?