Leaders for Bluefish

[Maine Guide]

Looking for some advice. I was fishing for stripers a few days back, and started pulling in small blues. I switched over to a steel leader, and could not get a hit. When I took off the steel leader, I started getting hits again, but the blues kept breaking me off.

I've read before that many of you will use heavy monofilament or flourocarbon rather than a steel leader. What is the minimum pound test that you will use (even for the bigger blues)? What length? How do you prefer to attach to the main line? direct or with barrell swivel, etc.?

Thanks for the advice.