I have played in Ballroom Dance Bands ,English French Traditional bands and in almost every case dancing the dances, or studying the dances will help set the tempo.By carefully looking at the dancers feet you can also quickly see if you are playing too fast or slow. For English Dancing if you are playing too fast the steps taken by the dancers will be smaller to enable them to keep up with the music. French Dancers take smaller steps so their music is played much faster than ours.
The most difficult place to play set speed dancing is C # House some like fast tempo, others slower .All sorts of hand signals pass between the dancers and the band ,some say speed up, others slow down.It is a place where you cannot win.
Al