A properly designed 4-1 will give more HP at the top end but at the expense of midrange torque.
A properly designed 4-2-1 will give more midrange torque but you lose the top end.

So there is no "best header". Like cams, or gears or tires, some are better for top end while others are better for midrange.

At Mid-Ohio you're usually better off with a Tri-Y
At Road Atlanta you'll probably want the 4-1.