The scale you show, which comes from the beginning of this post, is the reason I've become so involved with this thread.
The offset changes in conjunction with the wheel width changes are increasingly worse. As I've said multiple times...the offset should not change (much). If the ideal offset for the 6.5" wheel is +53 then the ideal offset for the 8.0" wheel is +53. I realize inward clearance becomes an issue but that simply means the wheel is too wide.
Finally, a +48 mm offset works well on most (if not all) Subarus and will give you a nice selection of wheels. Stick with that number (for any width wheel) and you will be happy with your wheel purchase.