Why not just use the Legacy banned list?
This would be of course the easiest way especially since we wouldn’t be responsible for the list. The frequent criticisms brought against us would be rendered useless since the DCI would be responsible. But we would be neglecting the format by making life easy! A special format with 100 cards also requires an individual banned list that covers the idiosyncracies of this format. The Legacy banned list is made with a “60 Card / 4 of each” frame of reference and is only useful in that type of environment.