Maximum mast rake with the sixteen is when you've gone block to block and still can maintain a little tension along the leech of the sail. It varies with the profile of the mainsheet block system you have. But in any case you should be able to use a low profile rig with max mast rake and still have enough rim left on the rotation stop to be sufficient. If not, you might have to replace the mast base. These sometimes get worn down, and are much easier to replace than the mast step.