Here’s the final-ish version of the clamped V4 carriage. Heatsink is super rigid now, and the screws pulled everything right together; no filing, sanding, or chiseling required.
It is mostly backwards compatible with Eric Lien’s cooling duct, but I couldn’t quite match the angle when I re-created everything. So, I CADed up a new one and I have that going on the printer now. What you see in the photos is an old one I printed a few weeks ago. As you can see, it fits, but it’s not perfect.