I uploaded some modifications to the neck assembly, added a screw-hole (for 3mm x 6mm screw) to mount the Head-center to the neck-round-top so you don't have to glue it to the neck-round-top, use 3mm x 8mm screws to put the neck-round-top left and right part together.

Made some small holes in the neck-round-bottom and neck-top to screw it together with a 2mm self-tapping screw. More space in the neck-bottom-right for servo cables, use 3mm x 8mm screw to assemble the neck-bottom right and left, I use glue to hold the nut in place.

I modified the eye-back-left and right to make more space for the servo-horns to move.

A modification is made to the body-front and body-front-door, I added holes for magnets (neodyne magnet 6mm x 3mm) to keep the front-door closed.

Made two holes in the body top for the cables. Made a flenge to the arm hinge axle so you don't have to glue in to the hinge.

Credits for my friend Ben for the redesign of the head-center part and the solar charge panel.