Well, the good news about the last map is: you don't have to kill that OP Elder to get all 6 drops, and the drop rates are phenomenal.

And one of the 5-stamina maps has 20 MC???

20/24 = 5/6 of MC at max yield

5/12 stamina ratio means anything better than 50% drop rates would make that map flat out better (at 50% would mean final is technically better due to slightly less charisma used). Of course, this also assumes you are able to get all necessary kills in the final map. Also assumes drop rates are about 90%