C-Beam bundle Questions

I'm looking at the C-Beam Bundle for a single axis project and I have a couple of questions.

- Will a NEMA 17 step motor fit the end cap supplied in the bundle? I need limited torque for this application so will need to go with either a NEMA 14 or NEMA 17 stepper motor. It appears the bundle is made to work with a NEMA 23 sized stepper motor so I'm unsure a NEMA 17 motor will bolt to the end cap.

- Does the flexible coupling work with both the NEMA 23 and NEMA 17 step motors?

Thanks!