The nature of Photoshop & CorelDRAW is different. PS is an image editing software based on Raster, where CDR is a Graphic Design Software based on Vectors. There has been a mistake. If your design is based on logo or typography or picture or abstract, then it is the best option for a CDR. The illustrator is the simplest choice when the T-Shirt design is made of a logo or text based graphic. Naturally – most of the professional designers will be using both of them before editing Photoshop photographs to add text.Go to site BlackBearMerch and there's everything about T-shirt Design who make on CorelDrawX8.
Are you a T shirt printer? A designer for long or short run.
In my area most small shops are doing 1 to 5 color shirts in a vector app of their choice.
High end ( simulated process color) longer runs are being done in a mixed bag of vector/raster with the separations done via a dedicated RIP for screen printing.
All short run high end shirts are being done via an inkjet or dyd sublimation process and that can be any application and the inkjets all use RGB PNG or JPG files.