What's your optimal rest time in between sets? 
The recommendation is 2-5 mins but curious what works for you and why?

i have no clue if this is good to do but i don't rest more than like 15s, what i do is rotate muscles. so like bicep curls -> plank -> hamstring curl and repeat. each muscle should get enough time to rest, but your overall central nervous system would not i suppose

depends. 5-7min for training pure strength (the purpose of the rest period is to fully recover so that you can put in max effort on the next set). 30s-2min for training aerobic capacity or muscular endurance

Searchcaster