This is an idea I came up with a few years ago but haven't filmed it until now.
Quite basic but very useful in many type of glue ups. Total height of clamping caul is enough to slide the parallell clamps under without tilting them. The height below the caul is enough to fit clamp heads underneath.
The feet are movable to don't interfere with clamp positions. Screw in the feet and routed t-track in the bottom side of the caul.