To some people a 240 gyuto is big, huge. My sink is adequate at 29" x 16 x 10.
Why are double basins important to you?
It has to do with how I hand wash dishes. I keep one basin half filled with hot soapy water in the morning and again while I cook in the evening -- so I wash as I go. With one basin I can't do that, as you just end up rinsing food, protein juices, etc into the dish water. I also find that there are circumstance when having segregated wash bowls is handy (when dealing with proteins for instance). But mostly, it is related to hand washing dishes that can't go in the dishwasher. I've become very efficient in use of water, and when I have to hand wash in single-basin sinks, I end up using a lot more water.
There is a cult of ignorance in the United States...nurtured by the false notion that democracy means that “my ignorance is just as good as your knowledge.” -- Isaac Asimov