I have software that helps me choose my arrow spine, weight and length. It also helps me set up my sites.
My target arrows will weigh as low as I am legally aloud to shoot. 5gr/pound is the lowest anyone should go. Reason I do this is because I don't judge yardage well so I make up for that by owning a really fast bow and shooting light arrows.
My hunting bow will have different arrows that weigh a little more, (like 50 to 75grs more). I can do that because I will have a different bow for hunting then I do for 3d and target.
If you happen to get as obsessed with archery like I have you might own four or five bows like me. I know, crazy eh. Just don't tell my wife.