I have a 27" draw and 70# and sell archery equipment for a job. I shoot 400 spine easton arrows. I have found that a little underspined arrows are more forgiving. But only to a certain point.At your specs you would be a 340 spine easton(beman). As for the tip weight I feel speed is more advantageous than weight. If you do the calculations on two arrows, one 300grain and one 450grain, shot at 70 pounds and 29" draw, the one weighing 150 grains more will only hit with 4lbs more kinetic energy but dramatically less velocity. To me its much better to be able to flatline 10 to 20yards farther and eliminate all that estimating when actually taking the shot hunting. Instead of a 0-20 yard first pin you could shoot a 0-30 yard first pin. Then no matter where the animal is out to that distance all you gotta do is put the pin on it and squeeze the trigger, alot less estimating is involved. If i were you i would drop to a 100 grain tip. use your arrow length to decide spin. It takes 50grains of tip weight to effect an arrows spine as much as one inch of arrow shaft, which weighs less than 10 grains. In example a 27" arrow with 100grain tip would flex more than a 26" arrow with a 140grain tip. hope this helps
Aaron
