I have been looking for the most authentic tobacco flavour for awhile. My advice is to just give up. What you will find find is that most of the tobacco flavours in the market taste kinda sweet like caramel/coffee or floral kinda like an unlit clove cigarette.
Cigarettes taste like that cos of all the chemicals in it. It is near impossible to replicate that taste. Just try the 'safe' tobacco flavours like RY4 or hangsen. I prefer the ry4 cos it is sweeter and has a nice caramel taste. Good luck!