Just as another idea, I like to use a back off set with my players when using the 5,4,3,2,1 cluster method. This would involve just repping out with as many reps as you can on your last set with the weight that you used in the cluster. Having spoken to Ash I know that he uses slighltly higher percentages than me but with longer rests between clusters. I use about 10 sec rests with a weight that you could perform approx 10 reps with. In your back off set if you are getting more than 10 reps than you went too light in your cluster sets. With Ash’s method you may only get out 6-8 reps.