That really depends on the friends, but with ele advantage and assuming they have a char atk eidolon, break point is about 100% assault (assuming both LB0). If they have an elemental eidolon, then the break-even point is much higher, if they don't have ele advantage, a bit lower. So if you're high rank, Takemikazuchi might be worth considering, otherwise I'd stick to Girimehkala.