Hey Paul, thanks for your question, just to clarify, I am not employed by Get Strength, I provide the answers as a free services to interested people, in using bands ideally you will work off of a percentage of your best lift, this starting percentage is not set in stone, I have some of my rugby players who start a cycle of band use using 40% whilst other will use 50% to begin with, so I would look at your progressions for bench press like this:
week 1 50% bands 8 x 3 reps
week 2 52.5% bands 8 x 3 reps
week 3 55% bands 8 x 3 reps
week 4 50% 2 bands 6 x 3 reps
week 5 52.5% 2 bands 6 x 3 reps
week 6 55% 2 bands 6 x 3 reps
and squat like this:
week 1 60% 1 light bands 10 x 2 reps
week 2 62.5% 1 light bands 10 x 2 reps
week 3 65% 1 light bands 10 x 2 reps
week 4 60% 1 medium bands 8 x 2 reps
week 5 62.5% 1 medium bands 8 x 2 reps
week 6 55% 1 medium bands 8 x 2 reps
cheers, ash