I think being able to choose when a missed IBB is made up makes up for any that are missed. In our game, sabreclub followed my first missed walk to his leadfoot pitcher with an IBB to Wills, and used the second (in the 8th) to set up runners at first and second to start the 9th.
It helped greatly that Dick "Bullet Arm" Brown gunned down all three runners trying to steal, Wills twice and Willie Davis once.
The games should definitely be played at Normal speed, not Fast.