You're fine with your original sizes and choice. Just go ahead and order the tires. The ME880 is one of the finest Metzeler tires produced for it's intended purpose...a hard compound high mileaage tire.
If you want some good prices on those 880s, try
Southwest Moto Tires. They have free shipping if you order 2 tires. I can just about throw a rock from my backyard and hit this tire store. They are widely known on the internet on just about all motorcycle forums.
