4 fabric lvl4 + 6 marble + 6 steel + 4 plank seemed well balanced to me
... and the 6-6-4 graftings were required by a storyline quest when I did the woodelves...
Tip : fullfill first the whole zone with extra lvl1 fabrics to produce faster the goods for the graftings sites and remove them as and when you are ready to build new graftings...