I would like to ask:

 

 

 

Should I use 400 PC Points to buy these two helmets in order to replace my farseer and archer helmet?

They ONLY work if you have the full set.

OK is that a no then?

I have the mage helm and its only +6 to all defense stats. Still looks awesome though.

Helms only work with full void set, even then i dont recommend them for their bad defense, only one I think is worth it is the range void set as it adds some damage bonus to damage, while for magic its practically nothing and for meele its same as wearing normal meele armor