Spine doesn't matter as much as some people think with field points. However when you put steel fletching on the front end of an arrow, it starts to become important.
Your arrows are probably a little stiff for your setup. Unless you can increase your draw weight or stretch your arrows, just sight in for the broadheads and you'll be good.
This is part of the reason a lot of guys have two bows. One for hunting and one for competition or just general practice and messing about with bows.
Allen