Spurlock shimming method.

[jolly roger]

>I know what a buttress does, and the ribs are the constraining element.
>Once again, the assembly is crowned and will support a considerable load
>before it is ever put into the rim. The rim does not support crown - the
>ribs and panel compression do. 
>

Hi Ron.
             Interesting hypothesis,  you trying to say that there will be
no difference with the board supported at the perimeter, or not.
Well I suggest you put a 100lb weight in the centre of of an unsupported
board and measure the movement of crown, then do the same with the board
glued into the piano, and let us know the results.
Roger