Making a wooden bow case.

I'd go with #2. Mark and saw carefully. Clean the edge up with a block plane, card scraper, or just a sanding block to remove the saw marks.

David Marks made a tool chest on the Woodworks TV show by gluing up the entire box--all six sides, then using a saw (it was his 20" band saw, I think) to slice the top off. You could do it on a table saw too, one side at a time. Use feather boards to make sure the box stays against the rip fence.

--Steve

And don't cut all the way through the sides. Leave a heavy sixteenth and cut through the remaining with a razor knife or hand saw, then clean up the edges with a plane.

Make one box then cut it in half. Some use a bandsaw but I like a table saw. I set the height of the blade about 1/32" less than the thickness of the wood so that you almost cut the top off. Use a utility knife to cut the top free then plane it smooth.