I think you should save your resources and wait for a good 6*. you're very close to complete act 7 and you'll have high chances to get a great 6* champs.at the point you're in the game i think you need to invest in your 6* roster.but if you don't have a very large roster of 6* and you need a new champ that will help you in 7.3/4,BWCV is a great choice,she helped me a lot in act 7. spidey99 is also great option especially for annoying mystics like Mojo&Dorm.good luck!
I think you should save your resources and wait for a good 6*. you're very close to complete act 7 and you'll have high chances to get a great 6* champs.at the point you're in the game i think you need to invest in your 6* roster.but if you don't have a very large roster of 6* and you need a new champ that will help you in 7.3/4,BWCV is a great choice,she helped me a lot in act 7. spidey99 is also great option especially for annoying mystics like Mojo&Dorm.good luck! These are great 6 stars I'd go s99