Just met this local (by local, he lives 5 blocks away in my suburb neighborhood!!) framebuilder who raced Keirin professionally for 17 years in Japan and even represented the country on the national team. I was showing him my Ironman and talking about Tange. He said Tange 1 is nice and light, but he always preferred racing with Tange 2, because while slightly heavier, the frame didn't flex as much as a result of barely thicker tubing!

So sometimes one tube isn't necessarily always better than the other -- it all depends on the purpose and use of the bike =]