What are good Brussels Sprout varieties to grow in Zone 5b?

I'd like to try my hand at growing Brussels Sprouts this year. What varieties grow best in Zone 5b? I have acreage so I would like to purchase both hybrids and open pollinated...

Do I need to worry about cross pollination?

Can BS be grown throughout the winter if grown in a cold frame or hoop-house?

Would appreciate your help and any helpful tips you might have regarding growing BS. :-)
Thanks!!
Glenda

Brussels sprouts seem to be the crop that gives me the most trouble. I tried Diabolo and Long Island Improved last year (both recommended for Zone 5 or 6 on several web sites) and got big plants but only tiny sprouts by the time frost came.

Other recommended varieties for our region are Bubbles, Tasty Nuggets, Oliver and Jade Cross. If I get my courage up I'll try one of those this year.

Thanks Don!!
The Bubbles variety has come up in articles I've found. I think I'll find that one and give it a try!
Good luck with yours, and thanks for your help! :)

Glenda