hello mucker. when i used the sabre router, the vacum bed had less holes in it, probably spaced at 40mm centres. it wasnt just holes, if i can explain. you had 4mm holes through into the sacrifial bed into the vacum, with a 20mmmm hole in the sacrificial bed. looking at it from the side it was "t" shaped. the small hole gives suction, then the bigger recess gives more, resulting in a better hold. Thats as clear as mud i know but difficult to explain. I think you have to many holes there, less is best i feel.

regards alex.