I don't know about magic boost or magical accuracy settings, but for weapons harvester and ahserion combines would be really good if Ahserion was more common. As an AT you gotta remember with the upgraded overdrive trigger you can reach cap magic boost easier than other classes and going PvP attack may be a good option.
Idium Strike, Rocket Punch, Heatburst or skills I would like to max out at 8 while keeping the other 3 AOE skills at 3. If AOE oriented, max the 3 AOE skills and have like 3 for the single target heavy hitters.