Rest between sets
Rest is something that is very well based on the individual. Now the least amount of the rest means the higher the intensity but you don’t want to get into the exercise so fast that the rest between wasn’t adequate to allow you to push to your full 100% during that set. So you have to find a balance. Now when i say rest is very well based on the individual i mean it in terms of a individuals cardiovascular capabilities. Some may have to take longer between sets then other, but if the times are getting out of hand it might start to be time to implement cardio into your routine to build up your cardiovascular performance so you can train with more intensity. Now with your three sets (warmup, feeler, working) you will have 3 different durations. For your warm up set you shouldn’t be taxed to the point where your out of breath or to the point where the muscles went to failure so rest here doesn’t need to be crazy long, maybe 30-45 sec. Your next set being your feeler set going into your working will be where you will need time to properly recover. Depending on the exercise your rest here could be anywhere from 1-3 minutes. It’s a pretty large gap, but here’s why. Your body's first go to energy source is adenosine triphosphate (ATP). ATP is a high energy molecule that stores the energy we need to do almost anything. But the more energy we need to expend the more ATP we use and the longer it takes to regenerate(3m being fully restored). So the big compound lifts like squats and deadlifts that will require more rest because of how much stress it causes to the body. And exercises like chest presses, shoulder presses, pulldowns, curls, extensions etc. even though if in the working sets probably don’t need 3 minutes of rest to require the energy needed to perform an exercise like these.