I've been working on my water grid and farming the guardian raids as suggested here and traded in 20 of the treasures for the axe. I'm now at 30 treasures again and wondering if it'd be better to get the second axe to 1 star it or get the lance instead. For reference, I'm still using 4 raid SR weapons in the water grid. I'm not sure what the better decision would be since each copy of a weapon I purchase keeps getting more expensive until it resets for the month.