I just came across this too (from something published in 2005)
"Preferred males were those exhibiting the higher number of ocelli in the train, but surprisingly females seemed to prefer males with shorter tails. This was unpredictable because we also found that the longer the train, the more dominant the male," they say. The female preference for both high number of ocelli and shorter tail gave the idea that females may actually prefer the visual perception of a dense cluster of ocelli than a diluted number of ocelli over a large surface. "We calculated the ocelli density and found that it did explain female choice."