For my previous post on how many colored sources you should put in your mana bases, I adapted Frank Karsten's simulation code to the London Mulligan rules change, and to make recommendations based on how many lands you want to play. In doing so, I made two errors: first, the tables for Commander decks do not take into account the free mulligan, or the turn one draw. Second, I changed the assumed mulligan strategy to be more aggressive; the effect of this change dominated over the effect of the London Mulligan, invalidating my comment on the matter.