600 sq. cm. = 93 sq. in.
630 sq. cm. = 98 sq. in.
660 sq. cm. = 102 sq. in.
Of course, those are approximations and Head measures from the outside of the frame IIRC. The Prestige Tour, or Trisys 300 in the USA, was offered in the 600 and 660. During the same time, the Pro Tour 630, aka (Trisys) Pro Tour 280 and the Trisys 260 aka Radical Tour was offered in the 630. The Trisys 270 aka Graphite Tour was offered in the 600 and 660.