I don't see a need for it. You can get unibushings for the xx75 arrows as well, so that would let you rotate the nocks if you needed to. Also makes it easier to change them if one gets messed up. And makes your arrows more resistent to robin hoods.

If you wanted to stick with aluminums, but lose some weight this is what you could try instead.

Your current arrows should weigh around 555 grns. And you have an FOC of around 10%. That is with a tapered nock and 4 inch vanes. It may be it bit more or less depending on what type of vanes you use. And 30.5 inch arrows for a 30 inch draw is a tad long. I am suspecting you want the arrow to hang over the shelf? This bow should have a cut out riser letting you use a shorter arrow. Going with 4 inch feathers and a unibushing would put you at 551 grns. Not much of a differance at all really.

If you switched to a xx78 super slam 2512 at 29.5 inches with a 100 grn tip and 4 inch feathers it would put you at 491 grns and about the same FOC. That might gain you 20 fps over what you are shooting now. Doesn't hardly seem worth it to me. Not to mention they would cost more and you would have to retune your bow because of the larger diameter shaft and possibly a slight difference in spine. If you were going to shoot spots this would be a good arrow though.

That's not that old of a bow, I thought maybe you had something from the late 80's or something. I have a martin cheetah from around 96 or 97. It's a target bow though and has steel cables on it as well.

Good luck,
Paul