I have a Drive circuit; 2 main partitions. One is a control circuit, the other
is an output stage that is driving power. The current in the drive stage 
is substantial and on several channels. The current on the control partition
is low.

Consequently, I have the top half of the card with relatively low Cu density,
and the other 'loaded' to cover my power. I need to control 'warp and twist'
on this PWB and am concerned about the Cu distribution. I am not certain about
how this is done with a strucure like this. What is the mechanism 
for warping a card?  I don't neccessarily wan't to load up the layers with
Cu to balance the low density regions because of X-Y CTE concerns.
I cannot superimpose the two partitions on N/S and F/S because of
'edgy' 28V switching on the output stage - they must stay apart for signal 
integrity. It is a 10-lyr. with lyrs 2 and 9 being 2oz. full coverage.