I am running to a subpanel in a workshop 30 ft from my house. My house service is 200 amp. I plan to run a total of 135 ft to the workshop from a 60 amp breaker in my main panel with either 6-3 copper, or 2-3 aluminum to a sub-panel. 30 ft of the run will be underground, which I can put in conduit. If I can get the aluminum for less than the copper, should I go with that?