To be on the safe side, I'd make that a pretty early dinner, especially if you tend to order an appetizer, entree, and desert. I'd probably make the PS for about 5:30. That way you could have a nice leisurely dinner and still stake out a reasonably good viewing spot for Spectro. You could probably safely eat at 6:00, but you'd worry too much if the service was slow or if the bus or boat didn't arrive after a few minutes.