The sport wing will probably be fine for you. I live in a very windy city, so I took my dihedral down to 3" combined. It works very well and it is still stable. The more the dihedral, the more the plan tries to fly itself. That makes it difficult in high winds.

The wing span is 60 or 61 inches. If you knock it down to 58, I don't think you'll notice a thing. And you won't have to take that much out.

Keep in mind that the PT-40 is a flat-bottom trainer with a non-symetrical wing. It will never go too fast or roll too quickly. That means you'll outgrow the whole plane, not just the wing. On the other hand, you've always got a relaxing, Sunday flier to cruise around with.

I ended up converting mine to a taildragger, decreasing dihedral, and maximizing throws on all control surfaces. She's still a lazy plane. Rolls take forever and Immelman's are hilariously slow. It's a fun way to get going.