I’m not sure what you’re confused about. These are all constant current drivers in question. They have an output current and and a voltage range to where they will operate at nameplate current. If using any of them in series configuration you simply see how many modules will fit within the acceptable output voltage range. A 200 watt driver at 700ma will have higher acceptable voltage than a 200 watt driver at 1050ma, so more strips will fit in series connected 700ma driver.
Running eb gen2, the strips will run cooler and more efficiently at 700ma than 1050ma. So in example above, Budbrother spent a little mord money to have a more efficient light than the configurations you had been considering prior.