Like many Thing-O-Matic owners, I ran into many problems with the automated build platform and eventually replaced it with the simple heated build platform. I printed that way for most of a year, but I finally decided to revisit the ABP and see if its problems were fixable. Thanks to many Thingiverse users' contributions, I have finally found a combination of fixes that works!
With the modifications described here, I now have the ability to quickly switch the ABP and HBP on my TOM, with no need to change any home offsets or Gcode. The belt is now evenly tensioned, free of wrinkles and holds down to the build platform well. Also, since both platforms are removable, maintaining them is much easier.
Most of the design work here is due to others, but one key fix I discovered involves modifying the rollers. Read on for the details.