As someone who in class still uses 8 kg for most exercises but 12 kg for double-handed swings, some squats, and deadlifts (although I should be getting close to the point where I can try this weight for cleans and other exercises), I used my 20 lb. kb for most exercises, using the 15 lb. for the warm-up and one of the press series and the 25 lb. for the two arm swings.