You have the general idea.
Lined-out single fans will bloom and develop increase fairly quickly, so growers don't necessarily line out double fans, unless the variety is older and not in so much demand. Newer, more expensive plants are most often lined out as single fans. Also, they're sometimes planted out in blocks instead of single rows, but the main idea is that they're broken up into near-saleable units, both for harvesting & shipping convenience and to encourage increase. Optimally, you'd want the lined out plants to have re-established fairly well before digging and shipping. I think most growers allow between a couple of months to a full growing season before selling.
Lining out seedlings is similar. In order to conserve artificial lighting and space, many growers sow seed thickly, and then when the seedlings have outgrown their seedling pots, they're lined out into the field with wider spacing so that they may grow to first bloom without too much competition. From comments I've read here, growers tend to space seedlings on 6" - 9" centers in rows about a foot apart.
Timing depends on the climate. I knew growers in Northern California who did all their dividing and lining out in the late fall and winter because it was the only time they had available. In colder climates, you'd want the divisions to have enough time to re-establish well before winter. Seedlings sown and grown over winter inside and under lights will usually bloom the next year after lining out if it's done in early spring.
