Well, I am not sure about the spine consistency. All I can tell you is I have won more tourneys with the goldtip blems than I can remember. I think it has far more to do with the indian behind the bow than the stick being shot.
I have a buddy, Rusty Horne, who is one of the best shots I have ever shot with. I believe he would cut down a sappling, cut a nock out, and without feathers hit the 10 ring.
I often ask him about his set ups because I absolutely love dissecting every part of my arrow and building my "perfect" arrow. He often replies, " i don't know anything about any of that".
I say all that to say just get the arrows and shoot. If you're concerned about durability, foot them with an aluminum shaft. If you're seriously concerned about the durability, don't shoot anything that they will break on. I'd bet 95% of all the arrows out there shot into a concrete wall at point blank ranges will either shove the insert up in the shaft or have it bounce out.