This is my first five-inch build! My father is actually building an exact replica about 2,000 miles away in another state so we can share tuning/diffs and build ideas. I got help with the parts list from some people around me in the community.

Overall, the build went smoothly. I try to avoid tape and zip ties wherever possible, so I was meticulous about coming up with mounting solutions. The two that I think were most non-standard were:
1) Replacing the M2 hardware on two corners of the TBS Unify Pro so they would be way too long, then epoxying those into M3 standoffs to provide a mount solution for the VTX. This worked way better than I thought. The mount is rock solid, and I think any crash that could break it loose would also break loose every other component in the whole build and there wouldn't be a quad left to worry about.
2) Making some mount pegs by heat-shrinking 25mm M3 bolts and capping them with nylon lock nuts. I screwed these into the rear struts where the antenna mount normally goes, to give me some mounting for the receiver. Zip ties were unavoidable, but I'm not losing sleep over it.

After ten packs flown I can say that this build rocks. Having never flown a 5" before, but with plenty of stick time on tiny whoops and toothpicks I can say that this build absolutely shreds. Very smooth, locked in, responsive, with gobs of power. Intent on freestyle flying, I wasn't concerned with weight. The quad weighs 400g dry.

I haven't done any tuning yet, and I'm still flying stock PIDs and curves. It plays the Rick and Morty theme song on startup.

Videos of my fifth flight soaring on a crane near my apartment, flying at a football field, and the maiden below: