Yeah. Free 10 BSG is the best option here. Just let ppl pick 1 of the non-limited SSR and it's gonna be sweet.
If you need any help just pm me then. I can put Mara on support so you can sweep all main story stages with her lol. My ultimate goal is to make Super Pixie but atm you can only inherit Megidolaon from Lucifer and fusing him is gonna take half a year of grinding lol.