I'm a little puzzled by your question - "Create Content" is not under the Admin menu in a default Ubercart installation, and when you create content all the types are distinct, so creating a Product type would be on a different page than creating (for example) a Service type - it wouldn't be just a dropdown choice under Product. So I don't really know how to answer your question. Usually, you will just have two types, "Product" and "Product Kit", Product being used in the vast majority of things you sell unless you've defined a custom product type for some reason. In any case, the type of the item should not affect your payment setup. Perhaps you could post a few screen shots of what you're seeing so we can better understand what you're talking about.