After page 7, I made a jump to 14. There wasn't much traction gained on spinning inserts, so I'll comment on some things in this thread that are being over-complicated.
Spinning inserts allow the shaft to gain rotational speed faster, allowing them to stabilize flight in a shorter distance. However, this implies the inserts are spinning perfectly, unimpeded by hot melt, dried blood, dirt, excessive friction, etc.
A free spinning shaft will not aid in the rotational power of a single bevel broadhead. The forward momentum is what provides the massive majority of twisting force. However, think about the mass of the arrow shaft spinning, aiding in the rotation of the broadhead. Small, but measurable. On a much larger scale, the "Tea Cup" carnival ride pins you to the back of your seat when spinning fast. This same power is applied to your broadhead at initial impact with a fixed insert.
More steeply angled helical vanes DO increase drag and decrease arrow speed and max distance. Imagine if a plane wing was straight/parallel (that's a fighter jet, minimal lift force but very fast) or this / (exaggerated 747 wing or helical vane. Generates lift, or spin in an arrow). If the vane was very step helical, like capital I, it would literally be as aerodynamic as a brick wall. Straight vanes will ALWAYS be faster than helical vanes on the same arrow, but won't stabilize as well.
Five grains is insignificant to most whitetail hunter shooting 30 yards. In Bowmar's case, 5 grains can mean 4 inches of drop while shooting 65 yards at a water buffalo. If you want to nitpick five grains, weigh your individual vanes, nocks, inserts, and amount of glue or hotmelt you are using. there can be significant variances in those that add up to a lot with a finished arrow.
Also, Kurt, Fury From the Sky! I left 1-508 last year.