Ive machined a plenum board today and connected it to one of the extractors in the factory. Im getting excellent hold down but wondered if it can be improved even more by machining the squares smaller and grooves deeper or narrower?

Currently the squares are around 50mm and grooves are 8mm wide x around 5mm deep.

Will more airflow in the board (i.e. making the square smaller) give even more hold down force or not?

if anyone has any experience it would be great to offer any advice, Ill get some images posted once its all fixed in properly.

Cheers guys