Growing a hazelnut bush?

I plan on growing a hazelnut bush once the weather gets warmer and I have a few questions

How big do they get?
Should you plant more than one for cross breeding?
If you have one, can you give me any other tips?

Thank you
Update: Buffalo, NY area
Update 2: Billy Ray- yeah, I live on a big hunk of clay so I will try that

Nips- will do
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