: . . . this is some very tight-grained mahogany,
: and although lightweight it feels very hard like a more dense wood. I'm
: thinking it may be hard to bend, and also I think it's strength will allow
: a thinner rib.

Well, first try bending it with the aid of steam or heat. If you get some bad results, then try using thinner materials.

If you make it as thin as a shaving from your plane it will curl up on its own -- so ou know that at some point it WILL bend. The hope is to find a good thicknees, say 3/32 or 1/8th inch, which will bend easily into the desired shape. Two or three of these very thin pieces can then be laminated to form ribs of the desired or designed thickness.

Lamination has a few advantages advantages. First, the compression on the inside of the bend is less with a thinner strip, so there is less loss of strength, less breakage and loss when bending and a sharper bend can be obtained. 2nd, by laminating two or more strips you increase the resistance of the strips to springing back.

hope this helps

PGJ