Kapex dimension question

[live4ever]

Though it's not in hand yet, I'm starting to design my miter saw station for the Kapex.  I have a small shop and I'm literally paying for the small footprint of the Kapex as no other slider would fit without significant discomfort.  What is the distance the Kapex needs behind the rearmost mounting hole(s)?

 

[johnnyinnb]

I have mine at 8 5/8ths to the center of the hole