So I got the bessey extenders and they worked great. Problem was that my longer clamps are jorgensens not bessey, so I didn't have enough length for the whole table top, even with the extenders. But, I was able to glue up three of the four sections of the top with the extenders. For the last section, I had to get creative:
Attaching the clamps like that caused the top to bow, so I had to clamp it down to the bench in the middle to keep it flat. It worked out reasonably well.
Spent some time this weekend cutting the curves on the ends of the top and sanding the whole thing down. The top is now finished except for the finish. I'll post some pics later when I get a chance.