Originally Posted by
Geepig
How many spokes are you using? If you are using 36 and 3x then by the time you have built the wheel you will realize that some of what is applicable for larger wheels is irrelevant for 20" and smaller, as just getting the spokes in can be a challenge. Truing the wheel at the right kind of tension is what you need to focus on as smaller deviations in rim alignment are more important at such small sizes as the percentage effect of 1 mm out on a 700 wheel is much less than for a 20" wheel plus the spokes will be much stiffer on the small wheel and differences would be much more difficult to measure even if you could get the tool in.
After building my first 36 spoke 3x 20" wheel I realized just how easy large wheels are
For 406/20's I've done 28 & 32's radial, 2x, & 3 cross. I concur with your experience. Even the spoke wrench itself sometimes doesn't want to fit.
One such example of my handi-work:
20210821_090900 by
Richard Mozzarella, on Flickr
It looks pretty, but I confess I screwed up with an amateur mistake. The front is half-radial, 2x which I am proud of, but the rear is 2x. It will be rebuilt shortly with the proper 3x pattern when I find some 181/182mm spokes. I'm not exactly looking forward to it.