Here is the email and the PDF. I'm pretty sure the damper can't be moved back:
Looks like we can get to 14-15% max. However if there is room to move the Damper itself back, closer to the engine, and then bolt on a pulley to the front, we can then go to 15-20% very easily. I do not like to be more than a 15% UD for street cars though. You can get into charging issues, and cooling issues at low speed. We reserve 20-25% UD for racecar's only. See the attached PDF for what our damper looks like now. Picture the Ribs staying in the same place, and then the damper insides moving back. I have no clue if there is room. This is one of the longest dampers we build!