For me, I've done 26/32, 28/34, 30/34 and fused 30/34....
Of these, the 26/32 and fused 30/34 are my favorites.... 26/32 is just too much work getting a preferred coil size in my gear.... If you have the space in your atty and a power source that can handle what you throw at it, the bigger cores seem to be better....
I'm on a mech and after the ramp up of the 26/32 it's enjoyable.... I get about the same with the fused 30/34 while being a bit cooler with less ramp-up....