No, these 700x43 tires are not supposed to fit on this bike. No, I'm not going to tell you what I did to make them fit. What I will tell you is that I can build a nearly identical bike that will handily accommodate these tires like this bike appears to be doing.
Supposedly there's a ride coming up Saturday in Point Reyes station ( see Bruce Gordon's blog) and all of us might be riding on these big tires. I'm looking forward to it.