OP Jeff again:
Downtube's full-suspension model for $580 w/shipping is one of the only 20" folders with suspension unless you spend well over $1000. Therefore "trying, measuring, etc at a local bike shop" is not practical.
I took a risk buying from a small company and got burned.
There really aren't two sides to this story - Yan posted wrong info in two places on his site, took weeks to respond and then had no interest in owning up to his mistake or making me a satisfied customer. Telling me I can return the bike at my (large) expense is not in any way a satisfactory solution.
Yan's response above also says he never saw my video.
I send him two videos weeks apart, and he did tell me he saw the second but never told me he didn't see the first one showing the balky folding hinge.
Good customer service would include asking me to resend the video or ask me about it in more detail, not just ignoring it.