In the 10/20/Life book they talk about doing, for example RPE 7 with one top set. So would I do something like 60%, 65% and then for my last set do 70% (RPE 7)?
70% could be a rough guide but using RPE does not involve percentages. Your goal is to have 3 reps left in the tank on that day. For example if you did 225×5 at an RPE of 7, it would mean you think you could have done 8 total reps that set.