Say you wanted Morrigan's Robe, it can be done in 4 days.
Day1: Head on out to Zhayolm, and farm gears for a Card. Day2: Head to SilverSeas, and use the card to pop Don Porrogo, and you get a Nemain's Robe. Day3: Head to Bhaflau, and kill Long-Bowed Chariot. Wewt, Bodb's Robe. Day4: Head to Arrapago, and kill some Qiqirn Astrologers. OPE! Macha's Coat.
This could be done, as well as -ANY- Salvage item in 3 runs minimal. The only difference is that the Lv35 items are uber gay for drop rates (I think we're 0/8 on Lv35 items, more than likely a LOT more). And of course that the Morrigan and Ares Body's share the same NMs (Lv35 being the exception).
So whilst it is possible to get a Morrigan's Robe or an Ares Cuirass in 4 runs, it's unlikely because they made Lv35 drop items gay. Lv15 are kinda 100% varying on the zone, and a Lv25 item you want has a 1/6 chance dropping from the Ares Boss NM (Will drop 2 items from a pool of 6 (7 in Bhaflau)), and can drop double that item.
More and more information is being gathered on Salvage, with each boss having been defeated now multiple times. The only zone that still remains a mystery is Zhayolm, because getting Lv15 items from there requires a lot of hard work for little in return (Killing 30 Mobs in order to pop a Poroggo to kill to get an item, per example), and I'm not sure if any group has found or obtained any Lv35 items from Zhayolm yet. :<