You should do aizen really soon. As long as you can tank his damage and have some one to deal damage you can win. Or be a pussy like me and use noza to do both XD
Do you have any suggestions on how to beat the solo fight against Executor(first Gin battle). The damage he does pretty much 1 shots most of my heavy hitters and Mayuri can survive longer, but he still takes too much damage to beat him. How much defense should I have to survive the normal damage and the poison dot?