Doesn't this largely depend on how many bricks he needs?
Usually, you need 3 bricks for one of the Hime weapon FLBs. But if he needs just 1 brick per each Advent FLB, then is it not worth it? We're still talking 3 decent FLBs compared to one excellent one. I guess you can argue that "eventually you won't have those decent FLBs in your Grid" though.