Summary

Atoms for construction of hexagonal close packed unit cell (ball-and-stick model).
Model sizes (diameters):
Atoms - 14.7 mm;
Holes - 2 mm.

Example of final constructed model see on: https://skfb.ly/p9OUZ
In this example, bond lengthes between atoms within close-packed layer are 44 mm, and bond lengthes between atoms out of close-packed layer are 43 mm.