Mr Gnome,
Just as the printed article had flaws in it the subtraction method with have tool marks that may not appeal to your accuracy without hand cleaning up or a very light bead blast.
That's just the nature of the beast and just making you aware of it.

Looking at your examples you will need a 3D CAM program to produce much of this work so allow around £500 to 1K for a decent program otherwise you are limiting yourself too much.