I am in the process of upgrading a MTH Premier 20-3007-1 pacific to PS2. This was made in 1994 and came with a Suethe smoke unit. It also has a small 21mm flywheel on a Pittman motor. I can machine a new flywheel or make a sleeve to make the OD the same size used on newer steam with Pittman motors. The smallest tach tape is 27mm but I assume the ideal OD is what will work best with the tach sensor.
What is the more common flywheel diameter used today?
Also what would be a good MTH smoke unit to use with this USRA Pacific?