my dad makes his from scratch. and its seriously WAY less sweet than you think one would be. its almost 2:2 ratio of the syrup and Maker's Mark bourbon. it may have a little more syrup though. so its pretty strong. my dad says the more sugar you put in past the "perfect point" the less enjoyable it is.
PK: dunno if you know or not. but mint julips just have a sprig of mint in the cup.. like celery in a Bloody Mary.