You need to lighten the point weight to stiffen the shaft or cut it down. Like others have said, don't worry so much about how the bareshaft is flying, instead focus on where it is impacting.
If I were only 2-3 inches off my fletched shafts at 25 yards, I would fletch them up and shoot. But I do not shoot competition, so 3 inches is still a kill on a deer.
As far as the spine goes, i shoot 48# at my draw, out of a Omega longbow and 400's are perfect, 500's will miss by a foot or more, so don't be afraid to play with the 400's or even stiffer spines.