i’ve been making small batches of bulk sourdough bread loaves lately (2 to 4, sometimes even up to 8 loaves).
It saves time to make a bulk dough, then divide into loaves at the time of shaping. This is how pro bakers operate.
Here is a handy tool for the home baker you can use to help you calculate the size of the bulk dough.
I found that bulk doughs larger than 3.5 kg (about 7 lbs.) become quite difficult to mix by hand. Make more than this, and you’re generally going to need a commercial mixer!