Well, I've dual coiled the Rebirth. And I'm even less impressed with that than I was with a single coil. So I've gone back to a single coil, 4 mm. Nothing special with either single or dual but it's OK, I guess. I wouldn't buy it again and it's heading to the classies but it's not awful. But it's not special either. At least not in my opinion.
Seems I'm getting hard to please in my old age.