Hi Eileen,
I am not aware on any conversion charts for wine conditioner. I think it's all a matter of taste to determine the sweetness. If adding a conditioner, start with a small sample of wine, say a 375 ml bottle, add a few drops until you get to the desired sweetness. Then convert the calculation to larger quantities of wine to be treated. I would however suggest that you let your sample sit for a day and then taste it again to be sure of the sweetness, then when adding to the overall wine I would add 10-20% less. You can always add more but once it is added you can't take it out.
Rocco