There's a loaded question thats asked a lot
IMO....it's based on load capacity and bulk, for most standard capacity machines I use the 1 bushel basket method, what ever dry clothes fit into a basket with a slight mound, that's a load, Large capacity 1 1/2 busel basket, another way is to drop clothes into a machine, and when you reach the top of the tub, that's a full load, Do Not Pack them down!....but every machine does not handle each load the same, one machine may really turn them over and over, others may move the load slowly....agitator design has a lot to do with it also...and agitator stroke or arc....
odd that my mothers GE V12 with the ramp activator, lid instructions for loading, reommended large items on the bottom like sheets or jeans, then towels or shirts, and final socks and washcloths, like they are not going to roll over but stay in their place for the top vanes are not as aggressive as the bottom part is......
I just don't understand people who wash a small load with a large fill level, and then comment on the great rollover, yeah, if I wash one item at a time, I would have great rollover too.....I do have a lot of laundry, and even with 3 sets, I don't want to spend all day sometimes washing, so I have to wash "reality" loads, and make sure I don't overload and that the clothes are moving freely..........