For what you're doing, the track width should be focused on what you can produce accurately. If you're etching your boards in a tank that consitently circulates the fluids and maintains proper temperature control you should have no trouble with 0.010 tracks, though it's not hard to overetch them.

Power supplies should go over 0.080" or larger, and, in fact, the larger the better, i.e. try to leave as much copper on the board as possible and use the area not used for signal as ground or power plane. You are, of course, at liberty to vary the track width of your supply distribution foil as much as you like, but I really recommend staying above 0.080" on this attempt. It wouldn't be bad to keep your .010" tracks at least .010 away from any other artifact, and farther is better. Keep the distance between adjacent tracks even, too, so you can easily inspect the board when you're finished. Be sure to "ohm-out" the board before attaching any components. Shorts and opens are more easily fixed in the absence of components.

RE