Allomantic Gold allows one to see into their alternate future, and Feruchemic Copper allows someone to store recent memories. (I will Add Quote later) When Vin burns gold and touches her gold shadow she briefly has access to her gold shadows memories and thoughts. What id someone stored Copper while touching their gold shadow. I think they will probably have access to all of their gold shadow's memories at best and only recent memories at the least. And if skilled Allomancers can influence which gold shadow appears, think about how overpower it is. Want to learn how to be a banker, burn gold and then store copper. If a A-Gold F-Copper was a detective, and he wanted to solve a murder, create a gold shadow that witness the murder. I know that all of the Gold Shadow's information will not be accurate, but the closer they are to the current present, the more likely the information will be correct.