Drums worked a treat! New wheels and brakes installed, but I held off on covering them.
The reason is that I also laced the new rim on the old hub, an exercise in extreme trial and error. Even with an identical wheel to use an example, it took me four complete re-do tries to figure out the right angle to the first spoke. From there I worked fairly quickly, but the afternoon was spent.
The allen wrench for the cable catch on the brakes is normally in my airplane "quick kit" that has the most common tools needed to work on stuff. I guess gnomes must have come in the night and taken it, though, as it was nowhere to be found. I played the long odds that maybe I put a tool back where it belongs with the others, but no dice. My allen set was all there except the one I needed.
My diagnosis on what went wrong on the fast taxi attempt was validated. The left brake is tight - it's a wonder it wasn't pulling me left at slower speeds.
With no way to adjust it, I packed everything up and headed home. There was no point in even a slow taxi; I'll go back tomorrow with a wrench that fits to fix it.
Saturday the weather looks amiable and I may try for an early morning try.