Agree with starting with support. A doorway works well too. Other points are good too.
Think too about looking out rather than done. Some learners have a stripe of tape on the floor ahead of them like a road centerline to help them with that. Your rollers need to be really square to the line and centered for that to help vs complicate!
I think there’s a big difference between cheap rollers and quality – without spending e-motion or trutrainer coin. As I’ve posted before, big fan of Sportcrafters, both the product and the people. High value for the money, with options to upgrade as you might choose.