easy copy of bones for viewmodel stuff

vmcopy.py

import bpy
context = bpy.context
scene = context.scene

ob = context.selected_objects[0]
ob1 = context.selected_objects[1]
for pb in ob.pose.bones:
    # convert from pose to world
    
    for pb2 in ob1.pose.bones:
        
        if pb.name != pb2.name:
            continue
        
        mw = ob.convert_space(pose_bone=pb, 
            matrix=pb.matrix, 
            from_space='POSE', 
            to_space='WORLD')
        
        mp = ob1.convert_space(pose_bone=pb2,
            matrix=mw,
            from_space = 'WORLD',
            to_space = 'POSE')
        
        pb2.matrix = mp
        bpy.context.view_layer.update()

Be in pose mode. Ctrl+click in order source armature and dest armature. All bones that match names will be positioned in same place. Moves dest armature to the pose of the source armature.