Gear wise, the only Darklight piece that's really useful are the pants, so save at least 900 Philo tomes up for your relic weapon (which will make the biggest difference). Accessory wise, the Rose Gold set (and some Militia I believe), including the helmet, are the best pre-AF2 pieces for the slots, especially with Materia melding in mind. For everything besides your pants, the green crafted items are what you'll want pre-AF2.

The defense on these items are lower, so you may want a Darklight set for fights where you'll be getting hit a lot too, but the extra crit you'll get over the Darklight/AK drops will be way more beneficial when healing.

As far as AF2 goes, the accessories, body and pants are optimized real well. The problem is that you need 900 Mytho tomes to +1 your relic, and that is significantly more useful than burning 300 on an accessory or 800 on your body piece.