8 receivers? On just 2 hoses?
That would be a difficult plan indeed.
Sorry - I don't have enough data to answer your question.
Years ago some Airship thought that, just because a TriStar held 3 times as much fuel as a Victor, it could trail 6 receivers where a Victor could only trail 2. The fact that it only had one hose available didn't affect his thinking......
The A330 MRTT does not have an upper cargo floor or door - because it doesn't need one. There is an enormous amount of space in the underfloor cargo area - and no additional tanks are needed for the AAR role.
Whereas the A310 MRTT, when fitted with 4 additional center tanks, has restricted underfloor cargo space, hence needs an upper cargo door and cargo floor.
As for the 767, it falls somewhere between the 2. It doesn't have the wide body of either the A310 or A330 (both of which have an identical fuselage cross section) and thus cannot carry normal LD3 bins in pairs. It may be fitted with an extended center tank, if that's what the customer wants, or indeed an upper deck cargo door. In fact, the customer can even ask for passenger windows and proper airline seating, which are of course standard in the A310 and A330.