I want to update the upstairs electrical in my house. The 2nd story is currently on one circuit, knob and tube. How many circuits should I run from my basement to my attic? I don't have a good place to install a sub-panel, so I'm not looking at that as an option. I have 4 bedrooms and 1 full bath upstairs. I'm thinking minimum 4 circuits (2 bedrooms/circuit and 2 circuits for bath). I want the bathroom to be ready for future installation of exhaust fan and wall heater. I'm planning on running 12/2 AWG. Can I run the wiring using those plastic cable stackers, or is that too many runs of wiring, too close together?