I've found that 3 recharge and 3 dmg SO's are the way to go. I've tried 4,2 and it gets the job done but it's worth it to sacrifice the little change in dmg for the extra time that 3 imps for out. For accucary, I use 6-slotted tactics and both rad infection and enervating field to reduce defense. This is more than enough dmg especially if you are soloing packs and not bosses.
For bosses, or even AVs you could switch to maybe 1 recharge and 5 dmg because when soloing only one villian, the imps sometimes can't even get past each other to hit the target. Having fewer imps will allow them ALL to hit the target with a lot more effeciency and dmg.
I always keep 3,3 on my imps and it works great. I am able to solo +4 bosses with ease. This is due to char though. I have it slotted 2 acc and 4 hold. Just throw out a char every 20 secs or so and watch your imps demolish those +3-4s. I even soloed a +5 (lvl 44) zues class titan. He never hit me once...charred him to death.
As far as AVs go though I dont know....Never really tried to solo one other than the envoy of shadows and I eventually beat him.
So in turn, I'm going to have to agree with the peeps that say 3 recharge and 3 dmg is the best for maximum xp.
