I would never surface plane a face with a jointer on a thin piece of wood. I consider it too risky, and too difficult to pass over the cutters with control. I would start with a squared large piece and cut off a slice and then put that through the thicknesser. Actually I have managed without using my surface planer for decades. A hand plane works for most jobs. I still have 10 digits untrimmed. Jointers are called “buzzers” in the antipodes! Well named. The best jointer is a suitably long hand plane.