ozarkhighlands has some good advice, try some nortons before you decide. I've had a bunch and overall I love them, but they are a high acid grape and can be a little harder to "tame" as far as acid goes. Chrysalis Vineyards in Virginia is supposed to be the best if you can make a trip there. I haven't had their Norton, although I'd love to!
My recommendation was based on how much trouble they are. I grow Nortons and I really don't spray much. They are resistant to most fungal infections that kill Vinifera grapes. But not all of course. They will do even better with a regular fungicide spray. With Vinifera you will have to keep a pretty regular schedule or they will suffer. With Nortons, I spray for bugs, but only spray for fungus in the spring. I may change that however, since I recently added some different vines and I prefer to keep the same schedule for all of them.
I think by regular spraying ozarkhighlands means a fungicide and possibly a pesticide. Definitely fungicide though.