you don't need stone towers AT ALL.
also, not a lot of people are going to attack your devourers, so there's no point of trying to burrow them, either. then the only use of your earth quanta is to increase the HP of your single gargoyle, which i think is really a waste.
suggestions of using
quanta properly:
- don't use towers. just go with your mark
- add more gargoyles
- add quicksands.