How to copy position, size from one armature to another? I have a armature A and made Copy armature B and C;

I went to editmode on B and moved arms bones a little down and made head bone bigger;

How to I apply same changes on C without manually moving the bones or without creating a new armature (ctrl+d from B)?

I was hoping for some button to copy armature from one to another (the bones structure is exacly the same even same names)

this is a quite challenging question, I don't expect an exact answer but directions to help me do what I want

thanks
While we can easily copy a pose from one armature to another I don't think there is a way to copy edit bone changes from armature to armature. This would mean creating a python script is the way.

As editing bone data in bpy.data.armatures[x].bones doesn't seem to work, we can go into edit mode to collect the bone data from the source armature, then apply that data to each destination armature in edit mode.

So getting close to an exact answer would be the following script, you should only have to change the rig names at the top.

import bpy

source_rig = 'metarig'
dest_rigs = ['metarig.001','metarig.002']

############

bone_data = {}

def edit_rig(rigname):
    bpy.ops.object.mode_set(mode='OBJECT')
    bpy.ops.object.select_all(action='DESELECT')

    bpy.data.objects[rigname].select = True
    bpy.context.scene.objects.active = bpy.data.objects[rigname]
    bpy.ops.object.mode_set(mode='EDIT')

edit_rig(source_rig)
for b in bpy.data.objects[source_rig].data.edit_bones:
    bone_data[b.name] = (b.head.copy(), b.tail.copy(), b.roll)

for arm_name in dest_rigs:
    edit_rig(arm_name)
    for b in bpy.data.objects[arm_name].data.edit_bones:
        b.head, b.tail, b.roll = bone_data[b.name]

bpy.ops.object.mode_set(mode='OBJECT')