Has anyone else tried using a bowed piece of wood as a caul together with the clamping elements to glue up panels or panel and frame pieces? The only problem I encountered was due to the limited amount the ram advances when the cam lever is rotated. I overcame this limitation by using a pair of clamping elements spaced rather close side by side and advancing them in alternating sequence. You can hold one end of the curved caul in close contact with your workpiece with one of Festool's standard L-shaped clamps while you jack the other end into fully clamped position (preferably backing your workpiece with the clamping arms described in Jerry Work's MFT Manual. Then move one of the clamping elements to the other end of the curved caul and finish clamping it into final position.
I have a couple pairs of Quick Grip clamps, but I am not a big fan of them, because too often they have slipped on me even after I squeezed them on using both hands. Maybe the strength of my hands is too little.
I "love" my Bessey K-bodies for HD glue-ups and for keeping things square, but my favorite for many jobs are lighter duty aluminum bar Jorgenson's. They are much lighter, and aliphatic glue (Tightbond) doesn't seem to react with or stick on their aluminum bars like it does with the galvanized steel bars of the Besseys or my pipe clamps. I am keeping my pipe clamps because I can join pipes anytime I need longer length, and they can produce a lot of clamping force. And they are relatively inexpensive.
When gluing up panels, and some odd-shaped pieces, I often use clamping dogs. These are very effective in drawing the ends of boards together, very fast to install (you simply drive them in with a hammer) and the marks they leave are in scrap that I cut off after glue up. And a dozen of them will store in a space not much larger than an iPod Nano.
Dave R.