I prefer the unibushings vs. the Super swage, simply because it's more durable i.e it can take nock end hits better than the swage.

As for spine you may find the 2315s a bit weak @ 76 pounds if your draw length (not arrow length) is 29" or greater. While they are a 340 class spine, you've got a big heavy outsert on the front which does weaken them up quite a bit. I would say without being able to test shoot any shafts beforehand you should look into a 2415/2514.

As for the diff between XX75s w/ bushings and XX78's...there is not a big diff...the XX78s are *slightly* more durable, and *slightly* straighter, but when talking alum, they are all extremely straight from the get-go.