Boring heads for the mill

[DanH]

Ok, please school me on what to look for when getting a boring head for my mill. I need to bore an accurate (light press fit) hole for a metric sized shaft in mild steel. All of my tooling is in english units so the dia is .591".

How do you choose between 2" and 3" boring heads?

I think I want to get boring bars with replaceable inserts.

I want to use it with both steel and aluminum.

Thanks for the help!
Dan