I shoot 28 inch arrow between 65-70 lbs. I am going to shoot 75gr / 100gr tip. The Beman chart shows that I should shoot the 400(ICS Hunter). However, I have had several people to say that I would be underspined if I shoot the 400s(ICS Hunter). What should I do? I do not want to damage my bow or myself for that matter. I shoot a Hoyt Powertec. I have already got some 400s, but I will change if I have too. Thanks for your time, GOD BLESS!!!!!!!!!!!