I am planning on running some booster draft tournaments, and want to make sure I am well supplied. The best case scenario is that each player takes 8 of one color and 8 of another color (assuming a typical 40% land spread). Realistically this doesn't happen, though. Sometimes there's more of one color than another in the draft packs. Some people go mono-color. Some people might be poor players and go with a color they don't have strong cards in (this is very common in red and green) which increases demand for that 'overloaded' color (while decreasing demand for another).
So the 'best all around' would be 4 land per color per person. So for a 10 player draft I should have 40 land of each color.
The 'worst case scenario' (while realistically impossible) would be 17 land of the same color for every person. So a 10 player draft would be 170 land of each color (since I don't know ahead of time which color will get 'overloaded' as such).
In summary, For a magic booster draft of
N players, how many of each land should I have available to accommodate a reasonably likely scenario?