Thanks, Brian!
Had a little more progress last night. I got everything for the LED rack wired up. I first taped off the locations for the LEDs (I didnt want to mark them), then drilled 1/4" holes next to each LED for wire routing. I also drilled 1/8" holes in the plastic end pieces to route wiring entirely inside the rack. Here's how it ended up inside the plastic ends. I ended up using 16 AWG wire, which is certainly more than necessary, but I wanted to use something with thick insulation and this fit the bill. I may still fill all the holes with something, but we'll get there down the road.
And then here it is all prewired before soldering. I used a couple of handy tools to get the wires where I needed them, particularly the picks and precision pliers. I used one red wire to make the polarity obvious coming out of the light rack.
I wired everything up with my 20W/40W soldering station, and it worked well. I don't have a ton of experience soldering onto circuit boards, but I managed. I much prefer using my butane iron (if anyone's shopping, I love
this one in particular, which I've used for 5 years or more), but those type would have gotten way too hot for this application. Once done, and after leaving myself 6' of line for future expansion, I was ready to test it out.
And it actually worked! I've got a variable wall wart to give me an dimming input voltage, but it only gives me an option of between 4-9V for dimming. It's pretty crappy (it actually puts out 9.4V when switched on the 6V setting, so I've got to be careful when I use it). I'll get some more images of it once I hang it over the current tank.