Working on a couple of Yost SOFs, and want to use a floating laminated coaming with a keyhole shape. Trying for something lighter and perhaps more attractive than a set of stacked rings. I've done a floating laminated coaming before, but that was a simple oval and lacking the thigh braces.
Simplest idea I can come up with is to glue a block of wood on the inside of the coaming.
Is this how people do it? Can I use cedar or does it need to be hardwood? Do you use a block the full height of the coaming? I know I saw this posted somewhere, but haven't found it again with much searching.
Any specifics, or alternatives, would be appreciated. The 2 alternatives I've thought of, laminating the keyhole shape or using a keyhole-shaped baseplate under a floating coaming, don't seem like great ideas to me.

Thanks very much,
Jeff