I'm upgrading my Rainbow Rose, she's at her 3rd stage now and Rainbow Growth Stone seems to be a wall for me atm, gotta roll gacha to get more but I still feel like I need to wait for a good 300 FS banner before doing that, because I really need OP units like Corbett, Pavonia, Adlay, Zinnia... The current 300 FS banner doesn't look good to me I think and I don't have a lot of FS, I'm not sure if 300 FS banners are common or rare ?