I too use 90-100% VG on all my Cartos, Vivi's, CE3-4 T3's DCCartos if it is thick (100%VG) I can't let my cartos sit unused for very long. They don't want to vape very good if they have sat with liquid in them. (cartos)
Now vivis and CE3's I tend to have to play with sometimes to get them to wick VG good. (make the wick at little looser) I can't vape PG so I use any where from 5-10% Distilled water along with the flavoring % so a lot of time it is really 80-90% VG the other 10-20% is flavoring and H2O