J., You must have misunderstood my posting. The 60' radius is what the
top would be braced at right out of the oven and bone dry. By the time
humidity reaches 50% you will have around a 25'. So actually, the method
described above would stand a better chance of fairing than pretty much
any other method. If a top is braced to a 60' radius when dried with the
intention of achieving a 25' radius at 50%, you would see it flatten to as
low as aroundn 60' in extreme dryness. At this point the guitar will be
buzzing all over if you could play it, but your fingers would be bleeding
too much to play due to the barbed wire fret ends poking out.
The Martins and Gibsons would be buzzing like mad by 35%, cracked all
over at 30%, and virtually irrepairable collapsed by 20%. Hopefully no one
has any Olsons out thier because they would be splinters by about 40%.
Seriously though, 8-10% is far outside of a reasonable range for pretty
much anything made of wood. Homes can get pretty close to that here in
Michigan in the winter, and I tell people if they don't keep thier
instruments humidified then expect to have major problems and void all
warranties.