So lets say i wanna awaken Spica, can i use 2 cc1 silver + 1gold archer, or it has to be 3 gold / 3 cc1 silvers?

Also if my math is good, i need 6 silvers per 1 awakening, so on this pic:
http://pokit.org/get/img/c6262803855...a0eff8ae65.png
I would need 1 more Elaine to be able to awaken thetis

Btw what about gold? I think i heard we need tons of gold for awakening?