I have a Sovereign XS-2A Pro with the 8" coil. Well, I think it is actually around 7.5". Would there be any advantage in getting a Sunray 8" coil. How much more depth and target separation would I get from the Sunray 8" if any. Or would it be about the same as what I already have. I am also thinking of getting the 12" coil from Sunray. Or should I just get the 12" and keep the 8" Minelab coil that I have already? Thanks.