As far as I know, everyone uses the newer TC arms on the team, including Hiro and Andy. The old ones are pretty heavy.
Positions 1, 3 and 5 are the same holes as the old rear arms. Numbers are probably different... but 3 from the new rear arm, is equivilent to the middle position on the old arm (not sure what number they use... probably 2). 2 on the new arm is right inbetween the middle and outer hole on the old arms.
position 2 and 4 on the new arms is equivalent to the holes on the old arms. 3 is right inbetween the old arms holes, and 1 is half a hole further out than the outermost hole.
Not sure if that helps any... Maybe I'll make some sort of a diagram/cheat sheet later on if I have time. Pretty much everyone uses the newer arms on their setups though.
-Korey