Brown Ale Hops

Which of these hops would you use in a brown ale with what hop schedule? I have hallertau, willamette and liberty.  ive seen these 3 used in other recipes. 
I was thinking:
60 mins - 1oz Willamette
30 mins - 1oz Hallertau
15 mins - 0.5oz of Willamette and 0.5oz of Hallertau
According to Beersmith: IBUs 22

Should I use the liberty instead?  Any and all input is appreciated!