Witch's Letter Gift

The reason I buy them is to increase rarity and raise the level link cap (you can't break the level cap without raising 5 characters). This means there's not much value in buying colors for which you have almost no SR materials. Considering quests and tower攻略, strong SRs for each color are: Blue ★Florence, (Amleth) Green ★Cordie, ●Merlin, ▲Nina, (Meltie) Red ▲Dian Orange ●Primavera, ●Mimi ★ is Attacker, ● is Support, ▲ has potential use in specific places, () are not to worry about early on but are strong. Looking at it this way, since strong characters are concentrated in Green, attribute tickets are a Green-only choice. Or, aim for Blue for Florence (Florence can also be obtained through Fate and Invitation). Probably, in terms of short-term efficiency... attribute tickets for Green, Fate and Invitation for Florence, that would be good. Also need to somehow obtain Primavera and Mimi (especially Primavera, so how about aiming for it by exchanging gold letters with coins?). To be continued