Thanks for the link, great work and nice scratch videos too!
Bp has chosen this faderbox dimensions for the stability and now with the rubber underneath is perfectly stable.
The peculiarity of bp faderbox and the difference from a mixer is that if you want you can cut the deck A at the same time in normal and hamster mode so you can make a combo cut using the left wall (hamster for me) and right wall (normal), I didn't use this in the battle for obvious reasons, it's only just for fun but maybe it can be an idea for your project too.