is it a terrible idea to try and build a 20” set as a first go?
No. Given the likely component choices, small wheels have much more latitude for build errors while remaining usable than large ones. Just don't try 36H 4X om a 20" rim unless you know what you're letting yourself in for.
No. Given the likely component choices, small wheels have much more latitude for build errors while remaining usable than large ones. Just don't try 36H 4X om a 20" rim unless you know what you're letting yourself in for.