Hunters who shoot any type of bow please help 10 points best answer?

I would not be concerned with speed at all. The two most important considerations are accuracy and penetration, do not let anyone tell you otherwise. That heavier arrow will penetrate way better. Proper spine will help it to shoot more accurately. Lots of practice will help you hit your target. Set at 70 and a proper arrow it will slice through a bull elk like butter. I would go to a reputable bow shop and have them help you set it up. There are too many variables to get it right over the net.