Looking for flats and 4-inch square pots.
Do you want true 4 inch pots? or 3 inch pots that are often called 4 inchers in the nurseries?
the 3 inch ones fit 18 per rectangular flats or 25 per square flat.
the true 4 inchers fit 16 per square flat and don't really fit well in the rectangular flats.
do you need any gallons?