No worries.... APA's put more emphasis on the hops. I do not know much about Brewers Gold hops (I believe they are British), so I cannot comment on them as a bittering hop. However, I have seen many APA recipe's that use strictly Cascade as both the bittering and aroma hop. If you really wanted to learn about Cascade use them as both.
The last APA I brewed had this schedule....
Cascade 1oz. 60
Cascade 1oz. 15
Cascade 1oz. Flame out
Cascade 1/2. oz. dry
It turned out spectacular and won my friend's independent APA blind taste competition with 12 other homebrew entries.