Here is a breakdown on the chart assuming that each square is 1 cm. I have included the cm and the inches (2.54 cm = 1 inch).
Gaston Gaudio
21cm x 7cm or 8.27" x 2.76"
Guillermo Coria
12cm x 3cm or 4.72" x 1.18"
Lleyton Hewitt
24cm x 6cm or 9.45" x 2.36"
Roger Federer
16cm x 5cm or 6.30" x 1.97"
Andy Roddick
16cm x 4cm or 6.30" x 1.57"
Marat Safin
19cm x 7cm or 7.48" x 2.76"
Andre Agassi
10cm x 3cm or 3.94" x 1.18"
JC Ferrero
18cm x 4cm or 7.09" x 1.57"
Rafael Nadal
15cm x 4cm or 5.91" x 1.57"
Tommy Haas
19cm x 5cm or 7.48" x 1.97"
Nicolas Kiefer
23cm x 6cm or 9.06" x 2.36"
If this chart is accurate, I really feel sorry for Andre Agassi and Guillermo Coria
Cheers,
KS