Welcome aboard, Steven!
There's no right or wrong with leader length
or size. Gary Yamamoto likes a long leader
just like Shaw, but personally, I don't like long
leaders. That's just my preference.
I always use leaders on all my gear. They'll be
anywhere from 4# - 15# depending on what,
where, and when I'm fishing.
Most common for me is 8#.
Length? Depends. Most often I'll stretch my
arms out two lengths while pulling a leader off
the spool.
Again, there's no right or wrong to your question,
it's all personal preference based on experience,
as you've read from Cap and A-Jay.