Here's a direct quote from what I was told:
"The manufacturer has internal QA requirements for working (bonded) side only. Only the working side affects sharpening. We know that imperfect back side drives some of our customers crazy. It's very easy to eliminate bowing by gluing a couple of tape strips to back side close to ends. After that, the positioning of diamonds will be always the same."
Personally, I think once it's secure, the only difference the bowing will make is how deep it sets not how consistently the stone is installed. After talking with several people about them, some that have them, like them very much and highly recommend them, I'm going to try them anyways. There is quite a bit of difference in the texture for the venev, they feel more like water stones than they do diamond plates. I'm personally really curious how they sharpen.
I'll take some pictures this weekend when they're clamped down in the kme so you can see how they set.