The tactic of using 20 or so and loading a little in each one is definitely alot of micro-management. Personally speaking, if someone is willing to invest that much time to seperate it all, and has enough energy to build them all, then more power to them. Personally, I tend to use a couple transports as dummies to soak up some damage, but not 20. Also, even without a ZPG, if you owned say 10 planets, that is 125k possible energy per planet. If your smart, and build Econ 3 stations, your resources will not take that big of a hit if you had to activate 2 planets worth of reactors to do it. I personally also build a mk2 and mk3 reactor on every planet I take over, in case I need extra energy for later on in the game.