I don't think that anyone would dispute that the E55 is the loser here, where smoothness is concerned.
I owned the 80 Lux for some time, and had my hands on the E60 for some time, although I did not own it. The 80 Lux is a fantastic lens, and one of my favorites of all time, but in some lighting scenarios it could have quite harsh boke. It also has more CA, IIRC. The E60 is not perfect, but it is overall just an amazingly well behaved lens with beautiful boke. Of all 50s I have tried, I only like the 50 Lux M ASPH better, in the department of smooth boke. There is a lot to say for the variants of the 50 Planar as well though, but it doesn't have as smooth boke by far.
I guess if you want to torture test the boke (which is really the only place where there is a qualitative preference of the E60 over the 80 Lux), put bright lights in the background. Christmas lights, sun-lit branches against the sky, metal fences, those kinds of scenes.