You can use it on Joker sets but then...it's not really a Joker set anymore. For any big barbell movement in the 5/3/1 program, you have a shitload of freedom to use just about any movement (outside of your main movements) by programming it as part of your supplemental movement. And since there are numerous supplemental set/rep schemes in the 5/3/1 program, your only dilemma is choosing what to use. As always, account for the supplemental work in your total program; DO NOT DO A TEMPLATE! Do a PROGRAM.