The best way (I'm told) is to shoot 3 of your arrows as normal, to get a good central grouping. Then shoot 3
unfletched arrows of the same type/size, using exactly the same aiming point. If the bare shafts fly to the right, the spine is too light. If they fly left, the spine is too heavy. You may well have to de-fletch some of your arrows to do this & then re-fletch them afterwards. Alternatively, beg, borrow or steal a spine-gauge
