Board Thread:Questions and Answers/@comment-64.233.173.223-20150425034435/@comment-26044650-20150425042851

It's a good idea to take advantage of the Crystal Sale going on - you get more Crystals (up to 40% extra) for slightly less money (about 5% off) and then wait for the Better Chance of Getting S Rank Treasures event if you want to get the best bang for your buck.

As for the tickets, I have no idea. It doesn't say if it applies to tickets, but it can't hurt to hoard them and try it when the BCoGSRT event comes back.

I don't think BCoGRST applies to the Great/Good Treasure Chests, as it does explicably say "Increases chances of S rank treasures" and Great/Good Treasure Chests doesn't even carry S rank treasures at all.