I'd go with a mixture of T-Slot Track in the Spoil board around the outer edges and a matrix of Tapped holes.
The T-slot allows quick and easy clamping of large pieces.
The Matrix of holes allows you to clamp small parts easily and just about any where on the bed and nearly always means you can find a place on your part to clamp.

The pain of tapping all those holes is worth the effort IME.!! . . .