Hey guys, So i've done 6-8 large scale, dining/ conference tables for clients and when I'm doing just a single joint with two larger slabs I get great results. However, lately i've had clients requesting lumber that's tougher/ more expensive in large slab form. So, I've been doing large glue-ups. This current job I'm about to start i'm building three 10' x 4' 6/4 walnut tables. So I'll have 6-8 boards that i'll be biscuit-ing & jointing together for the width. On previous tables like this I've had a little movement from one board to the next of 1/16"-1/8". I've been using the 3/4" Bessy pipe clamps to joint, along with a small, flat piece of aluminum I-beam to clamp across the top to keep the surface flat.

My question is, are the clamps causing my issue since they bend a bit when tightened (not overtightening)? would parallel clamps from dubuque, bessey, jet, etc fix this? is it just going to happen across a 4' span of 6-8 boards gluing up? or is my old porter cable biscuit jointer just giving too much play (doesn't feel like it, they're a nice, tight fit sliding in)

Thanks guys, just trying to figure out what I need to do to save myself hours of surfacing these tables after the glue-ups.