I've never used the carb tabs but I think they are plenty self explanatory. I believe it's one drop per 12 oz bottle and 2 drops for the bomber bottles.
With dextrose, I use about 3.5 oz for 5 gallons of cider. (This is hard cider at 7% ABV, not apple wine - but I think it should be the same) I shoot for around 2 volumes which is sort of a draught style (IMO) and not champagne like.
Here's a good calculator for determining the weight of your priming sugar: