I finally found some time to get back to the box. I was about to say that cutting the shape with the band saw is a critical step, but then I realized that they are all critical steps. I use a small 10" Rikon band saw which has a vertical clearance of only 3 1/2". This severely limits the size of the boxes I can make.
Working with these smaller blocks of wood can sometimes put my precious fingers dangerously close to the saw blade. Believe me, I have a great respect for that blade, but more about that in some later posting.
I used gouges and power burrs to take out wood on the sides and approach the final rough shape of the arches.
The band sawing exposed a crack in the wood which wasn't visible from the outside. However, the piece seems strong, so I may be able to use some filler. I always save fine wood dust from sawing, sanding or power forming in a small tin for filling in such cracks or kerf cut marks.
Here is the new rough shape. There is still a lot of forming to do on the arches. I have left the sides square, not making the bottom box side angle cuts yet, so that I can easily saw off the box top at a right angle to the side, and parallel to the base.