Anyone working with a grid style high volume vacuum table?

I could use some feedback regarding manifold grid sizing & spoil board types.

Also, anyone using MDF as a spoil board?
I need to determine the vacuum & flow required to use such material.

I've seen many pictures of such setups but never actually talked to anyone who has used one.

My application is cutting out aluminum plate lettering on a 4'x4' table. The layouts are random so pods & gaskets are out of question.

I'm going to use a large Gardner Denver rotary lobe blower that I found in a scrap yard for my vacuum.
I also have some 2" dia pneumatic plunger valves that I plan on using for switching between 4 zones automatically depending on spindle location.

Any input would be appreciated!

Thanks!

Chris