Winter rye establishment into established clover was mentioned in another thread. It will establish, but not as thick in clover as in a new seeding. What I'm seeing on one of my plots this spring is backing that up. I have a plot that's been seeded with WR/clover for 3 straight years in the fall. Last year I expanded the plot by spraying and seeding. The new portion has a much greater amount of WR than the old. I guess that's the long way of saying, once the clover is established, you'll get some WR to come up, but I do not think you'd ever be "smothered" in rye.