Save quartz or spend for Cu Alter?

Since you have Waver for your Jalter support, basically you dont need Cu Alter. again, you have altera(great damage dealer). i dont find any reason for you to pull on culter banner beside its your husbando or whatever it is. your composition team already good enough to sweep every quest.

But,
Cu Alter has the highest damage among berserker who deal 1.5x damage to all servant type. Protection from Arrow and Battle Continuation keep cu safe from damage. you'll find it hard to kill him.And you'll never see Culter Solo rate up anymore since it never happened in JP server.

THAT'S UP TO YOU!

You have Waver, Heracles and Jalter that makes the game into easy mode at the beginning~
Now you just have to pull Minamoto Raikou and Merlin to complete the game with very easy mode~