herkman,
I don't agree with your comment that the RAAF C130H fleet has been flogged 'mainly because our customer the ARMY'. Constant circuit training, fighter evasion and low level operations especially in Iraq at ~300KIAS have done the damage.
In regards to C130 centre sections, the C130A had an entirely different centre section from other C130s. The original C130B/E centre section was also considerable different and really only designed for the C130B with an AUW of 135.0K. It deteriated rapidly in the C130E with the higher AUW and almost all C130E aircraft (RAAF, USAF, RCAF, RNZAF and RAF) had their centre section replaced with an upgraded centre section that is basically the same (but not identical) as the centre section used in the C130H/J. Except for an experimental carbon fibre centre section the USAF MC130H is really the only other centre section out there. Its increased strength is not so much for operating at 175.0K but to tolerate the increased fatigue spectrum of the mission and to increase the LOT of what is a very expensive and capable specialised aircraft.
I assume that the 'many 16 hour flights' in your log book either included a refuel or you had the internal ferry tank fitted?
Beez51