The manufacturers all have websites with info. A google search will find online places to buy them, there is also Ebay, though I think a sink is an item where it's going to be much better to just buy it locally.
As for going with the type with one big bowl and a small disposal bowl, I had this type and replaced it a year ago. IMO, this is the most useless type of sink there is. They are predicated on the idea that you will use the small bowl to scrap of food from dishes, prior to washing them in the other bowl. I just scape mine into the garbage can and put it in the dishwasher which is right there. And most of the stuff I want to send down the disposal comes from food prep work, which I do over the large bowl, so that's where I want the disposal. For example, if I'm rinsing off, peeling, vegs, I do it over the large bowl, then send the scraps right down.
My strong sink preference is 2 deep bowls, one large, one about 2/3. Take a look at the Kohler Marsala. This gives you one big bowl that you can fit even most large pot/pans, and a second bowl that is big enough as a functional second one. It's very convenient to have that second clean sink there when you suddenly need it during some cooking operation. The Marsala also has very deep bowls, which make a big diff. Now when I use the spray head, there is much less blowback. And the drains are located in the rear corners of the bowls, giving you more availabe fuctional bowl space. Also, it's set up as a single faucet model, with the faucet going in the back area behind the center divider. This frees up what would normally be used for sill area in the back where faucets would be, allowing both bowls to go back another
3", giving you more bowl room.
If I wasn;t getting the above, I'd go with either a double bowl or one large bowl.