I plan on making this ahead of time for a 4th of July party and bottling it in 1 gallon jugs with a screw on cap. How long do you think it would keep like this?
On the day of the party I would just pour from the jugs into a dispenser and maybe sweeten it the day of the party?? We have these cool dispensers that we got at Sam's Club during the summer that are two pieces. The main part holds the beverage and has a spout for dispensing and it sits on a bowl shaped stand that you put ice in to keep the beverage cold without watering it down.
Here is the dispenser...we've used it primarily for Trash Can Margaritas: http://www.samsclub.com/sams/shop/product.jsp?productId=198812&navAction=
Or search their site for "Unbreakable Beverage Dispenser" if link is dead