I'm not sure I completely understand all of this. The initial comment I
saw
was "  NOTHING CLOSER THAN 3 x TRACK WIDTH", which I enterpret
as traces close on the same layer. If used for the ground plane, then
possibly the impedance would not be met. As for the ground plane strip
size,......I've heard this referred to as the "signal return path" and it
likes
to see 5X the trace size (At least the EMC guys preach this). But now try

to hold this going accross a series of connectors or BGA plane
clearances. Most of the time it's impossible at those locations.
Sometimes, even the signal traces may overlap a portion of the plane
clearance. I refer to that as the "lattice effect". That takes many
overlaps
in a series to really add up any real difference (lump sum effect).

Just my .02 cents

Groovy

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