My preference, based on experience is to run power from transformer handle(s) to a control panel, which has a toggle switch for each of my (76) blocks [plus the controllers for each of my 47 switches], and then run 14 gauge wire from each switch to its respective block. This gives max control when running conventional, and the ability to deaden sections of the layout when running command [DCS for me]. It also allows full control from a centralized layout.
For common (outside rail), I suggest using a bare wire (maybe 12 gauge if you can find it), looping completely around the layout with frequent drops to the outside rails.
You haven't mentioned wire gauge. I strongly recommend 14-gauge to reduce voltage drop on long runs.
