Just rotate the maps if you want silvers more than fangs. Would also keep grid from becoming too boring. That's what I do - need more witches and soldiers, so alternate between island and forest maps.
And 700 fangs? That's gonna cost some serious dough at this point...
ЗЫ. 1215 fangs so far... and 360 more to go in this two days. Gotta step up SC expenditure.