Still waiting for the military guys to reply but crewing was always the weak point on mil ops. In the 90's 216 were running at 2 crews per frame plus maybe an additional crew scratched form execs and standards. This was based on 8 frames and always caused delays and hold ups. Crewing at this ratio is insufficient to really support any extended slip patterns and other tasks. This meant that, except for a few slip patterns, most tasks involved the aircraft night-stopping along with the crew.
Considering the limitations that the RAF AT set up has imposed upon it by both the MOD and the treasury they do an excellent job. However, if one was setting up a company to do this type of operation exclusively for the RAF I doubt whether the L1011 would be the type of choice, nor would the crewing ratios be so poor and the engineers would have access to a large and readily available spares set.