Hello George
first of all Rudel was one of kind. On the quality of Kacha's pages, IMHO it is very good for a site which is, I think, based on secondary sources.
IMHO what is clear than all those fighter pilots with 1000 or moore sorties had began operational flying earlier than Hartmann. Barkhorn and Krupinski (1104 and 1100 combat sorties) had flew combat sorties even before the beginning of Oper Barbarossa, but of course Barkhorn was rather inactive in 45. Hackl (about 1000 combat sorties) was pre-war regular who fought throughout the war but was badly wounded twice, Rudorffer (1000 + combat sorties) also flew practically through the whole war.
If we look those high Eastern Front claimers who had fairly short careers, Batz (237 victories) amassed 445 combat sorties in 2⅟4 years, Beerenbrock (117 victories) amassed appr. 400 sorties in 1⅔ years in front-line unit and Birker (117 victories) 284 sorties in 1⅟4 years, it seems that appr 300 sorties per year was more or less max for fighter pilots in the Eastern Front. IIRC ground attack and Stuka pilots could amass sorties faster rate.
Juha