What is the small hole on rear wheel just above the braking surface for? Also, the included rim tape is made of a hard plastic material. Did you guys use this or did you buy real rim tape?

I have a set of Eurus with the same hole in the rear rim. I thought it was a drain but that doesn't make much sense. Maybe manufacturing? The hard plastic rim strips work fine. I have them on a set of Velomax wheels too. Center the valve stem hole carefully before you lay in the rest of the strip.

I believe the small hole you speak of, which mine have as well, is what is called a "weep" hole. It is designed to allow moisture buildup to exit the inside of the rim. As for the plastic rim strip. I have this one on the front and Velox rim tape on the back. I can't tell a bit of difference and performance hasn't been effected in the least.

What is the small hole on rear wheel just above the braking surface for? Also, the included rim tape is made of a hard plastic material. Did you guys use this or did you buy real rim tape?

I'm still using the green hard plastic Michelin strips that came with my Zondas. They work fine, and I don't have to worry about pinch flats from the spoke holes. :)