How to prepare a ginger lime drink mixer?
Not sure whether you will have a bartender or not but as a former Bartender here is how I would approach it.  You'll have to experiment in advance for the flavor you are trying to achieve.  Since everything you are working with is sharp I would make a ginger simple syrup. 1/2 water 1/2 household sugar and probably about a tablespoon of fresh grated ginger. Heat until all the sugar is melted and then let it steep until you are are happy with the ginger flavor. bottle it and keep it in the refrigerator.

I would start with:


1/4 oz ginger syrup
1 oz Whiskey
splash of fresh lime juice
garnish with a bruised basil leaf.


and adjust the measures until you get what you are looking for.

If you are looking for something sparkling try:


1 oz whiskey
2 oz ginger ale
1/2 oz Rose's Lime juice


with the same garnish.