It depends on what type of all-over printing you’re doing. If you’re printing on a finished garment, then you don’t need to have individual parts or elements. Just design the artwork larger than the garment size using a template.
Most people try to use one template for all sizes. This works OK in most instances, but it will result in the main image or focal point being smaller on larger shirts. You need to have a focal point smaller and toward the top of the template, with other filler information toward the sides and bottom. That way, when you transfer the smaller shirt, the image is where it needs to be, and when you print the larger shirt, it’s there as well. Color or secondary artwork fills the rest of the shirt.
If you’re printing a cut-and-sew design, you will need to use separate templates for the front, back, and sleeves. These parts would be transferred individually and then sewn together later in the process.
—Great Dane Graphics