[Marcus26]

Decreasing arrow point weight will NOT change the spine of the arrow. The spine is the amount that the arrow flexes and this has no relationship to point weight. The only difference it CAN make is that a heavier point may have a longer internal shaft, which will stiffen the arrow.
For wind drift weight and diametre are everything. Speed means nothing. If you go for FPS coming out of the bow then you will lose ALOT of FPS after 70m which will cost you more points.
Thinner = Better
Heavier = Better
Lighter = Worse

Also a heavy but thicker arrow can be as good as a thinner lighter arrow.