Dualboxing mage & warlock - thoughts / suggestions

I'm dualboxing a mage and a warlock, lvl 42 atm. The mage is speced arcane and the Warlock is speced destruction. I went with destro on the lock figuring it's the closest spec to the mage play style. I have been messing around with spells trying my best to match up spells w/ similar cast times together. Most of my leveling has been done through LFD so making sure I am putting out respectable DPS on both toons is a priority for me. I have all but dropped the Warlock DoTs from my rotation, as the trash in the leveling dungeons dies too quickly for the DoTs to be effective. With all that having been said, I'm interested in getting others thoughts and suggestions both on spec combination and any good spell pairings that will increase my efficiency and my dps.