The Creator 7 was made to produce web graphics, not printed products. That said, you can create an image big enough to print well. Many users here have created T-shirts and other products. The image below was created at 2880 x 2880. It is only 762KB at 72 DPI. It will upload to Vistaprint and looks just fine on a T-shirt. Depending on which service you are using for printed products, you may have to adjust the DPI to 300. You can use a number of 3rd party utilities to do that. I use xnView on a PC. It is a free utility. At 300 DPI the image below is 7.2MB in size. Just remember, increasing the DPI does not increase resolution. The only way to do that would be to use a vector image and The Creator does not support vector images.
So, make your graphic as large as you can, up to 2880 x 2880 ( max size that TC7 will export ) and try it out.