I don't know about Cat, but in same class Deere machines I have some published info. Their tests show on a 35d excavator (303cr class) a light use rate of .7gph and a heavy use rate of 1.2gph. A 325 skid steer (252b class) under light use is 1.8gph and 3.9gph under heavy use.
Hope this helps.
Frank