[ger21]

Nothing's easier than setting a part on the spoilboard, snd turning on the vacuum switch.
If your buying a Shop Sabre, buy it with a vacuum table.

No single hold down method will work perfectly for all parts, so you may need to do somethi g different when the job requires it.

[Joe Jones]

Yeah ... I tried to use The Force, but I am beginning to believe that really doesn't work.

[kmagyoyo]

The spoilboard needs an air tight surface underneath it, to hold the vacuum.
You also need to remove about 0.01" from each side of the MDF, to allow more flow through it Yes, as you expose more of the spoilboard, you get vacuum leaks, and holding force decreases.This is part of why you need very high flow rates.

^^^^This, and seal the edge of the spoilboard with paint or just run it through your edgebander if you have one.