[IBU] Gnome Root Beer Question

[Eric and Susan]

I think Gnome was the brand of extract for the IBU tent at the Des Moines 
Beerfest a few years back so I thought I would ask here.  I am making some 
root beer for a fund raiser at work and I don't want to look like the fool I 
am.

The directions on the Gnome root beer label say to use 4 lbs. of sugar and 
2 - 4 oz of extract.  What is the rate to get the best tasting root beer.

Your help is appreciated.

Eric