I'm sorry I don't have more time right now. I do need to add what I have learned in the past few years to my DCC in the Garden section. I use code 250 nickel-silver rail.
Briefly, I find that picking up power from the track, aside from a quick cleaning, actually works very well. Most G-scale locomotives have better pick-ups on their wheels, plus LGB's sliders, makes the locomotives reliable.
I built my garden RR before twisting wires and adding terminations was in vogue. After these techniques became the conventional wisdom, I went around my 35'x40' pike with a scope and didn't find that I had any problems.
I echo the use of rail clamps.
More, later, when I have some time...
Wiring For DCC