I cultipacked some brassicas into dead oat stubble in July and had pretty good luck with it. It wasn't quite as impressive as a plot on disked ground, but it looks pretty good. At the same time I planted that strip, I threw some seeds into the adjacent soybean field and I couldn't cultipack there. I checked this plot today and the seed I threw on the soybeans really didn't do anything. My soil is fairly sandy, so I think that hurts the broadcasting method without using a packer. I'm guessing you have more options when you have a great loam, but it can be a little tougher on sandy plots. Definitely worth a try either way though.