Culti packers have loose wheels.
You are building more of a land leveler.
Not a huge difference, but some. The loose wheels will pack seed in better, while a single roller will smooth the soil more, mashing high points.
Auction I was at, there was a home made one. Was a couple dozen old horse drawn sickle mower steel wheela on a shaft with a hitch. I think it even had 2 wings, it was very well made actually. They had a devil of a time loading it, was too heavy for the loader at the auction. Pretty neat, I would have taken a photo if I had a camera. I wonder how he accumulated all those mower wheels.
Your deal should work. Might want to figure out the weight you end up with first, so you don't get any suurprises....