This is what I do.
G1 X300 Y15 Z0.3 ; move the platform to purge extrusion
G92 E0 ; zero the extruded length
G1 F200 X395 E30 ; extrude 30mm of feed stock
G92 E0 ; zero the extruded length again
G1 X150 Y150 Z25 F12000 ; recenter and begin
Add that to your startup script right after the temp is set.
Make adjustments as desired of course.