I try to start a set every three minutes. That stretches out to 3:30 or four when things get heavy.

Lose the cable stuff, and the only curl worth doing is strict form with a straight bar. JMO. Do some dips, and add weight to them when you can. Do standing press as well.

You are young enough to handle a great deal of volume, and could squat three days a week. There are no upper and lower body days - lift three days a week and do it all.