I had the same problem as @thorsager , but my setup is a Satechi x1 slim keyboard and a magic trackpad.
So, here are the modifications:
1. Support Satechi x1 slim keyboard

2. Reduced sides between the keyboard and trackpad and both sides of the holder

3. Expand holes for charging cables

4. Reduced the number of holding pins

5. Moved the trackpad deeper to avoid accidental clicks

6. Added holes for the power switch of devices