Bienvenido a Kinograph @Carmelo
Very nice start on your project, and thank you for sharing your progress.
Regarding your question about the steppers, suggest you check out Roland’s all format scanner, in particular he is using NEMA23 with closed loop Integrated motor.
In Ronald’s project, the Reel is mounted directly on the stepper axle.
Look forward to seeing more of your project. Buena suerte!