I ride +15/-15.
I like it to be exactly the same both directions, because my aim is to be able to ride switch as well as I can regular.
I think the post above said that duck would help with your spinning, not necessarily, increased angles. The duck part feels right to me - but I don't have a good explanation as to why
Like the others said, try things out and see what is comfortable. I you want to ride switch the same as regular, having equal angles seems like a good place to start...