When designing teeth at the midline, it is best to create mirror mesial incisal, labial, and cervical embrasures. The midline is best managed with the vertical axis of the face. This is why I use BioCopy and preplan the case with a wax-up to simplify and provide a system for very predictable results.
Work from the midline distally (Design and Finishing Workflow). Choose the central with the largest root truck and set it to the midline using the 2D guide. Then remove the model and finish the proximal mesial of the single central