Number 34- Pedro Astacio
Pedro Astacio is one of the better starting pitchers in Colorado Rockies history. Overall, in parts of five seasons, he pitched to a 53-48 with an ERA of 5.43 (102 ERA+), a FIP of 4.75, and a pitching bWAR of 10.8.
In the three full seasons as a Rockie (he was acquired for Eric Young Sr. in the middle of 1997 and traded mid-season in 2001 for Scott Elarton), he also averaged 213 innings a season so he was one of the Rockies biggest innings eaters.
Number 35- Chad Bettis
Chad Bettis wore it for his entire tenure as a Rockie. In those seven seasons, he pitched to a 31-31 with an ERA of 5.12 (4.93 FIP and 93 ERA+) and a pitching bWAR of 3.6.
The next best player to wear the number was John Vander Wal and if he was an everyday player, he might actually be the winner but since he was largely a pinch-hitter, Bettis is the winner.