Well, tonight was a comedy of errors. My m.2 standoffs and custom connectors arrived, and I got to work on finally completing my build.
1. The USB and GPU connectors worked exactly as I hoped they did, and really cleaned up their respective cable arrangements. The 24-pin motherboard connector actually looked worse with the 90-degree interface; I ended up uninstalling that one, but I can live with two out of three.
2. It turns out, I ordered the wrong standoffs; Gigabyte uses a different screw, so the ones that arrived don't fit. I put in an order for the correct ones, but they're out of stock and won't arrive for another two weeks.
3. For all the time I spent getting the cables just
right, I ended up installing the heatsink upside-down on the m.2 drive (the manufacturer's logo
is on the face of the heatsink, and is plainly visible through the glass panel of my case). Worse, by the time I realized it, the glue on the thermal pads had apparently set, and I couldn't get it off the drive.
On the plus side, the heatsink works great, lowering the controller temp from 70 degrees Celsius down to 50-55, depending on workload. And since I didn't put any RGB in my PC, I can't actually see the upside-down text on it when it's dark. It just annoys me. I assume the glue will eventually weaken over multiple heating/cooling cycles (thus the silicone bands actually used to secure the heatsink, in addition to the adhesive), so maybe I'll be able to reverse it by the time the new standoffs arrive.