Hi Peter !!
When i play at a wedding or a party the men always invite the ladies to dance, and the band always play two songs for them to dance to, both at the same tempo. This is a tradition and all dancers at public dances in Sweden do this.
There for i have my songs in my "library" and i have for example one playlist for weddings and one playlist for partys and a third for playing at the local pub, The songs are the same BUT the came in different locations in my different playlists. Its easy for my to keep track of witch song "first or last", difficult to explain........
But you always play two fast songs together then two slow songs together, this is very important in Sweden.
And i am using the color as Same on the two fast ones, then another color for the slow ones. But in another playlist i might play the songs in a different order..... Hope you understand me, im not so god in writing in English.