Hi
I made lobelia tincture with Alcohol and just a little of vinegar and did not have any of those problems. I know what you mean about the film. That is fomr using the vinegar. I just make sure that I shake the bottle once in a while. I f I dont when I go to use the pippet there is a bit of film in the little container I just put that down the sink.
That was about 4 years ago and I still have the tincture to use now.
When you make any again I would use about 10% vinegar? might get rid of most of the problems.
Hope this helps
Tiggs