Hi Russ.  The trick is to set the depth of cut on the circular saw no deeper than necessary which makes the horizontal length of the blade that is immersed in the cut as short as possible.  If the curves are fairly gentle, then that should work fine.  If you have a smaller circular saw, or a jigsaw, those will work well also.  It wouldn't hurt to experiment a bit first so you can proceed with more confidence.  

Grant

Thanks Grant, I'll give that a try this evening.  The curves are fairly gentle over a 12 foot span.   If it looks like it will work, I'll get a nice new blade and move forward. 

Russ 

Russ,
When you buy that new blade, get a carbide blade, not a plywood blade. It will cut faster, tear less and and last a lot longer. I use a Porter-Cable trim saw, which is a worm-drive circular saw with a four-inch blade that cuts like a Skil saw but handles like a jig saw. Unfortunately, they are now three times the price that I paid fifteen years ago. -Wes

The skill saw with the blade set slightly deeper than the cut worked fine on my test panel.  There was no tendency to creep or get hung up when making the curved cut.

Russ 

Might be a bit late on this one, but have you thought about a Japanese saw. As you probably know, they cut on the "pull" and have very thin blades resulting in great control. One can literally split a pencil line with one of these.

I cut my Chesapeake 16 panels out with one.

Dave