Ok here goes again... I haven't done one of these question things for years
Firstly the Dark Art of pressing
Imagine a drum with a tight thin skin on it and a drum with a thicker skin on it.... Now get a drum stick and hit them, the thin skin will be more responsive that the thicker skin...
Now lets relate that to willow... Willows is made up of loads vessels lying on top of each other and the grain which is the bark from the end year growth.
Ok lets look at this as a box of straws lying on the table, the straws are now the sapwood and stick something hard with no holes in there for the grain.
Now all you need to do press with enough pressure to compress the top bit and take into account the grain is harder to press that then sapwood [we know this from our box of straws] to get the thin drum skin layer. We are after the thin drum skin layer aren't we.... [This is why is better to get hold of someone that takes this in account as opposed to running all the willow through on a same pressure run]
Ok brillant pressing is king I hear you say!!!!!
Well Now you shape a bat, it looks good, smells good and has the biggest edges in the world [I added that bit in for my amusement] The middle looks like it is in the right place.... Then you swing it, when this happens things change stuff due to physics makes that place where all the wood is just out of sync with where it should be. This is down to the balance and your swing speed so the profile is actually doing something to aid performance....
Then you get the collision with the ball, the way the bat reacts to that collision is to do with the willow not just pressing here but you've got that piece of willows natural frequencies and your man made stuff to take into account, also the profile shape is involved here and the handle!
So all of a sudden the profile shape and willow is doing quite a lot isnt it!
It is a very good question really... opinions comments now you maybe know a bit more?