lvl7 is best if you only consider supplies efficiency and disregard worker efficiency. as in you keep 8 workers set aside, dedicated to expeditions. the actual number of workers you must keep free for lvl 7 to be the most efficient is going to be less than 8, but 8 is what that chart assumes. im not going to try to calculate the magic number, it will be too high for me is all i need to know.
if you actually care what the workers are doing while theyre not on supply missions, lvl 9 is best.
if what youre looking for isnt efficiency, but organization and limited deviation from plans, lvl 6 may be best. only check the dock whenever a 3-man team finishes their job(ie anti-tank gun, oil well, etc) and only go on 3-man expeditions so there are no flunctuations in number of free workers. lvl 6 dock has the highest chance of getting a 3-man supply mission, even with 1 less slot.
btw havana and calcutta give supplies
if you actually care what the workers are doing while theyre not on supply missions, lvl 9 is best.
if what youre looking for isnt efficiency, but organization and limited deviation from plans, lvl 6 may be best. only check the dock whenever a 3-man team finishes their job(ie anti-tank gun, oil well, etc) and only go on 3-man expeditions so there are no flunctuations in number of free workers. lvl 6 dock has the highest chance of getting a 3-man supply mission, even with 1 less slot.
btw havana and calcutta give supplies