Re: Glycerin question?
Nix using fresh fruit. I'd think it would mold and cause all kinds of problems.
If you must flavor it with fruit use candy oil.
That said, there's plenty of fruit-flavored stuff on the market already. Why not let the tobacco notes shine through? Natural moassels are very hard to find on the american market.
With the glycerine, my advice is to be sparing... It adds to the clouds, but it also drowns the flavor. I've also found it helps to give it a day or two to sit and smooth out before smoking.