The more I look at the Yuichi design, the more simple it becomes. A bowl turning that's not scooped out; cut exactly in half; mortised with a horizontal boring rig fitted with an end mill and the various triangles and trapezoids glued in place.And of course a turning for the thingy that attaches the compression doohickey.
For whatever reason Yuichi chose a lamination for his bowl, solid stock could also be used. That thickness should be dimensionally stable in almost any hardwood. I like the acoustic properties of mahogany and maple in that order. Mahogany is easier to acquire in 16/4 and more stable in central-heating-land.C'mon Garland, you can do it!