I ran the Ribs, Linings, and Bass Bar through the Luthier's Friend thickness sander on May 24th. I took the ribs down to 1mm, the Bass Bar to 5.5 x 23 mm, and the Linings to 2 x 6 mm. The Luthier's Friend makes this type of accurate sanding very easy.
Normally one would not sand the Linings. I admit it's a but over the top... but it didn't take long, and makes for a much smoother transition between the ribs and plates. I will give them a bevel before using them.
The ribs are from Atlantic Violin Supply, as are the rest of the materials for this instrument. They have been prompt, helpful, and reasonably priced. Only the Linings and corner/end blocks are sourced elsewhere, they are from a chunk of willow I purchased from A&M last year.