I have enough at the moment to take one of the listed to R5. I have explored 100% Act 5, Chapter 1 and 2 and now I've completed Chapter 3 and have started Chapter 4. Of course, next step is to finish this chapter and either fully explore the rest of Act 5 or dive into Act 6.
My 6 Stars are Proxima Midnight and The Hood, but they're not past R1 and I started running suicides at the beginning of September. I wish I could take them all, but it is what it is and I'm going back on forth on who should be my next. Thanks so much!