Depending on what you are trying achieve with the number of layers
you may not be able to provide a breakout pattern as you describe.
The breakout , if any , will also depend on your BGA ball arrangement.
We successfully route up to 529 pin BGAs on two signal layers, and
two planes using 6/6 line and spacing and 50 mil pitch BGAs.

Tim Easterling
SCI Systems Inc.
(205) 882 4426

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