Avastar (rigging) question

Hi everyone! I have a Blender’s addon Avastar (for Second Life) question. I know some basic rigging, concepts etc, not professional rigger. I created custom mesh, adjusted Avastar default mesh to my custom mesh as best as I could to prepare it for later binding the armature. But head and eyes of my custom mesh are way different: head is much bigger and eyes too low as consequence. It’s a child mesh and Avastar default is for adult male and female meshes. Does anyone know how to adjust head and eyes rig here? Thank you very much in advance!