Just a comment. As mentioned it may be currently fashionable to use high VG juices, but PG is a much better carrier of flavour than VG, and provides a better throat hit. It means that you can use less flavouring and nicotine and still have a decent vape. Personally I vape at around 65%PG/35%VG. As for the oily taste, I think it may be more flavour related. I have had a couple of flavours which left my mouth feeling like it was coated, which is a little unpleasant. You may just need to try a different brand. That's the problem with DIY juices, it is all subjective and down to personal taste.