With a base income of 5, it was possible to get a single pick FTB of a +3 bonus using a commander with a 40% chance. Having roughly a coin-flip to get an FTB is not ideal, so I decreased base income from 5 to 4. This means you only have a 16% chance of getting a single pick FTB, which seems better to me. It doesn't impact any of the other starting combinations I mentioned in my first post.
Here's a sample game with 4 base income: https://www.warlight.net/MultiPlayer?GameID=12665666