I've shot NAP Thunderhead 125 since I started bowhunting in 1991. Be sure to take plenty of time to practice with the broadheads in place so that you know you can consistently place them in your target at varying ranges. As everyone knows, often the broadhead, whether fixed blade or expandable, will not shoot the same as field points. If that happens, then your bow is not really properly tuned.
To be consistently accurate at a wide range of distances, I must tune my bow with broadheads attached, which I do with the traditional paper tuning technigues.
Follow link for some tips on paper tuning.