Sterling Hops

Never used Sterling Hops. Just wondering how much for a 20 minute flavor addition?
My recipe:
10 Gallon batch
15#2row
2# Vienna Malt
WY2112
Nugget bittering
Sterling last 20 minutes
OG 1.050
IBUs about 35

This is my Psuedo Lager, how much hops do you use for the 20 minute addition?

At least two or three ounces.