I'm kinda new to this whole scene, I shot an old Bear bow about 5 years ago and then lost interest and now just bought a Mathews 2QXL. So anyway, I would like to know how to calculate arrow weight. I shoot Gold Tip, XT hunters in 55-75, they are 8.2 grains/inch. I use 125 grain combo points, 4" plastic vanes and plastic nocks. The arrows are cut right at 27.5 inches (without pioints and nocks). Can anyone help me figure out the weight. Thanks.