A few more pointers...Do a dry fit first. Use a strip of hardwood along each edge for your clamps to crush so you don't damage the edge of your table. Where your clamps touch the glue and the wood, you may get black stains in the wood, which may or may not get planed out...to avoid, lay a strip of plastic under the clamp. A strip of plastic works for keeping the cauls from sticking, also. I use a paint roller to spread the glue evenly and quickly. An even layer of glue, no dry spots, is the key. Get the pieces together before the glue dries out...that's why you do a dry run, so you aren't running around like a mad man to find something you forgot while the glue is drying in the open. Start clamping from one end and have somebody raise and lower boards to get them level as you tighten the clamps (this works instead of or along with the cauls). 10" apart is good, not much more. In 44" a pipe clamp will start to bow quite a bit. I use Jorgenson I beam bar clamps...they stay straight a lot better...just watch the amount of pressure top vs. bottom...even with cauls, if you apply way to much pressure to one side, you create a warped top. You should be able to remove the cauls once the clamps are tight...that's when you check the flatness of the top...adjust the clamp pressure so the top is flat...use a straight edge laid across the top as a guide. Another hint. If you get a stubborn board that won't line up, try putting a shim under the caul and forcing it into line...time is against you, though. If you have a friend, have them there to help. It sucks to need help when nobody is around. There is probably more, but these will help. That dry run will teach you a lot.