Apparently I'm not good enough to tell ...but I have a real hard time seeing how someone could honestly say that a '78 is more accurate than a '75 if both are straight, properly spined shafts, but that's just me.
If you are like me, with my curves I like to hunt, stump, target shoot, wing shoot -- anything really. So eventually a '78 will bend just like a '75 will. Both are great shafts for multi-purpose use, so if money is main consideration, then I say you will NOT be disappointed in the standard XX75 shafts. I have both, and have had success with both shafts.