From my memory, I could consistently win against +3's, assuming no incredibly bad streak of resists. However it was not as efficient as +2 or lower. I could kill +4's sometimes with luck, but it was very inconsistent, frustrating, and risky.
Grinding on +2's could still be a bit risky though, in the case of adds.
It's been a while since I was in the lower levels on my mage, but if my memory serves me well, the level difference only made a bigger impact at lower levels.
I don't feel much difference between grinding on greens and yellows, except that it's safer with greens. The exp seems around the same.
On the topic of clearcasting, I find the best spell for procing it is scorch. I got the idea off someone in these forums (I forget who, sorry). It's great because not only does it have a very small cast time, it's inherently a very mana efficient spell. Typically in normal instances, all I cast on the normal guys is scorch, and AM when clearcast procs. It reduces downtime greatly.
Grinding on +2's could still be a bit risky though, in the case of adds.
It's been a while since I was in the lower levels on my mage, but if my memory serves me well, the level difference only made a bigger impact at lower levels.
I don't feel much difference between grinding on greens and yellows, except that it's safer with greens. The exp seems around the same.
On the topic of clearcasting, I find the best spell for procing it is scorch. I got the idea off someone in these forums (I forget who, sorry). It's great because not only does it have a very small cast time, it's inherently a very mana efficient spell. Typically in normal instances, all I cast on the normal guys is scorch, and AM when clearcast procs. It reduces downtime greatly.
Less QQ more Pew Pew