Luftwaffe's Transport Craft Maintenance and Logistics

Does anybody have the data on the average maintenance and turnaround time of Luftwaffe's KGzbV or TG units during World War II? How many sorties per day could be made under ideal conditions, especially by Ju 52s and Me 323s? How do they manage their maintenance checks, do they have things similar to the ABC check system in modern aircraft maintenance? What's the readiness percentage of a KGzbV or TG at one time? In the case of long-range supply missions, do they use their aircraft to ferry aviation fuel for their own missions? Or in other words, were these Transportgeschwaders self-sufficient?