After a few hours of reading instructions, screwing and clamping things into place, then undoing it all and redoing it properly because I didn't read the instructions thoroughly enough, I got the 10m Moxon antenna assembled. The bent tubes were easy enough to straighten out, and the one tube that had 2cm broken off was still long enough to work with. I managed to lose a hose clamp somewhere along the way, but fortunately I was able to find another one that worked in one of my toolboxes. Ended up with a bunch of extra lock washers too that didn't seem to in the parts list in the manual.
Here's the feed point, which I'll probably zip tie (or some other tie) onto the beam.
It's a pretty big antenna, at right around 3.97m (12.4 feet) long. Here it is up against the car for some scale.
Now to figure out how I'm going to get it up into the air...