I tried one drop of Vape Wizard in about 15ml of a liquid I made using 7 different flavorings. It was originally pretty harsh/alcoholic and slightly perfumey/musty, and after the VW it was very smooth but the stronger flavors were greatly reduced in strength. Unfortunately it's now quite weak so I'm going to double one of the stronger flavorings I used and see how that goes. I'd suggest you start off trying one drop per 30ml Isis, or if you make smaller batches dilute a drop of the VW with some drops of PG in advance so you can use fractions of a drop.
Have you tried asharp's method of leaving it in sunlight to reduce harshness?