The big 41" arc had a few high spots, which I brought down 1/8" at a time.
Two of the corners are rounded with 3" radius. Marked that line and made 3 straight cuts to get closer to that curve. My plan is to use the new plane to round it out. (I just realized that my jigsaw has an attachment that lets you do fixed-raidus curves. Oops!)
Had Julie the artist pick a curve for the top, and made 3 cuts to approximate that, too.
All the cutting was with the circular saw.
Here's where things stand: