wiring should be run through the CENTER of the studs to avoid the
possibility of a nail or screw being driven into it. What I've always
done when putting in fiberglass is to cut a slit across the width of
the batt about 2/3 of the way through the fiberglass side (don't cut
into the paper). If done even reasonably close to the wire run, the
wire will nest right inside the slit that was made and the fiberglass
fits nicely around it. No worries about stuffing insulation behind or
in front of the wire.