The fuel fit was dependent on mission. By the book, the big tanks were not cleared for Auto-TF or even supersonic... but they did both. Eight-bomb fit with big tanks put you at or above (the then) heavy fit limits, but fit was reduced to 5 or 4 x 1000lbs bombs for later missions.
Recce jets predominantly flew in 3 or 4 tank fit throughout and the ALARM missions brought in the weird stick-a-tank-where-you-like fits.
The move to medium level (save for the recce jets) changed things around again, with big tanks making a return & also providing some much-needed lift when fighting thunderstorms. It also brought in the need to jettison tanks during spirited medium-level SAM evasion and the subsequent burn-down of tank stocks before the logistics caught up again.