Crown in New "D" board

[Bdshull@AOL.COM]

List,

I tackled my first new board project recently (I was a little crazy, because 
I was immersed in a grad program at the same time).  It was a 1926 Steinway D 
which had a board with reverse crown when a respectable wholesale rebuilder 
rebuilt it in 1987 - the rebuilder took the conservative downbearing 
approach, and when I tore the piano down it still had positive downbearing 
and a real sweet sound throughout the treble - and in my 1200 sq ft shop it 
seemed like it had some power, but in the hall it was a gutless truck (little 
treble power, 60 gr action).  The piano was used in a big hall and was 
frequently drowned out by the typical romantic concerto warhorses.   I wasn't 
sure ANY piano would pack enough punch for this venue, but a new board was 
the way to go.  I vended the belly work, and received the piano with new 
board and blank caps;  I set bearing, notched and pinned.  The soundboard 
shop I used is fairly conservative about following lighter Steinway crown 
specs (atmospheric+slightly crowned rib surfaces), shooting for a 62' radius; 
 we ended up with a board with maximum 5/16" crown in the longest span, 
3/16-1/4" in medium spans.  I immersed myself in Nick's Journal articles to 
try to understand setting bearing on a new board.  After 1 1/2 months strung, 
my assessment is that the piano sounds great, plenty of punch, good sustain.  
But more questions than answers about crown/downbearing.

So the questions:  How to decide bearing, arbitrarily by a fixed ideal angle 
for the different sections of the piano (such as .5 degrees in the low 
tenor/bass to 1.5 degrees in the treble)?  The board builder likes to load 
the board at the long bridge with gobars to simulate string pressure, then 
set bearing (1.5 degrees in the middle, to .5 at the ends).  Why not 
calculate downbearing based on the crown in the board (split the difference), 
or enough bearing to theoretically flatten the board?  Some combination of a 
theoretically ideal bearing and that resulting from the real-world crown in 
your new board, factoring your power/sustain goals based on usage and the 
acoustical environment of the piano, if known?  

I have a soundboard press in process, two pianos/new blanks waiting, and 
another piano (Steinway short scale Style 2 converted to modern treble long 
scale) coming back from the soundboard vendor just before Reno with a new 
board/blank bridge caps.  I am very interested in your thinking about these 
new soundboard crown/downbearing questions, collective list and soundboard 
experts [even Brian the reed organ rebuilder (sorry to hear about your 
collection woes, Brian), who has, I think, mused some himself about this?].

Bill Shull, RPT