(...) the Scorpion Harness is overkill (...)
Now here is where I'm inclined to disagree somewhat. If Darthstrife were to get the gear that I recommended, he would have +36 ACC on top the +10 ACC he gets from the ACC bonus job trait. That would give him +46 ACC for TPing, which is really nice for when you're fighting mobs that are usually Low to Mid IT. You tend to EXP on such mobs at that level, so I think Scorpion Harness would be best. If he were EXPing on VT to Low IT mobs, I'd say Jaridah(or Akinji) Peti would indeed produce the best results. I agree with Assault Jerkin being best though.
Over the past week or so I've been running an analysis on total accuracy vs. mob evasion at various levels to determine expected hit rate, and the result is I now agree with you. The SH is back on. Particularly if you're not getting as much acc from the waist slot (e.g. Swift Belt), the extra +5 ATK from the J.Peti is going to waste if you aren't achieving 85-90% hit rate. (Although the +5 ATK would cancel out the Swift Belt penalty.)
Also remember we've picked up a second ACC job trait. That's a total +22 at these levels now. That turned out to have some interesting effects in my acc vs. eva analysis -- the 60's levels are almost unaffected by the DEX:ACC change from 1:1 to 4:3 because of that extra +12. But I still come down in favor of the SH over the J.Peti, the total accuracy numbers just look better.
That analysis also indicates that if I ever get anything off Ose, I'd better seriously consider an Optical Hat to replace the lost accuracy from switching out the SH. (Of course it does depend on what sort of mobs you're fighting.) 85-90% while using meat is not trivial to reach against low IT -- it takes attention to the gear build to get there.
Swift Belt beats both of those.
I myself would only say that if it's used in conjunction with other Haste gear. 4% Haste on its own isn't going to give much benefit, surely? Unless you can stack some more on top of that to bring about 10% total from the gear build (and remembering the Walahra Turban is level 75), I would not be inclined to take the -5 ATK. I know once a certain base threshold is achieved, adding any haste adds damage, and that a haste build is very effective, but I would be suspicious of the effectiveness of once haste+4%/atk-5 piece in the 60's levels.
I think it's better to say the key to ACC is to maintain a 85-90% hit rate while TPing. If you have the proper gear, this usually leads to the best damage output since you're still landing most of your hits while keeping your hits consistently strong.
I'd agree completely with this. TP return from Vorpal is, however, very easily checked with a TP report line in the Penta macro, and is available in real time. Actual overall hit rate is really only measurable with a parser (which is why I've been doing a theoretical analysis, I don't have a parser) which as I understand it, is hard to check during a party? Eyeballing the hit rate is notoriously inaccurate.