Paul I think you probably wont regret the cost of the KD's. They do two important things more than this system and that firstly is they can push in the disconnected position to spot a wagon anywhere it can be pushed to. I also suspect that they will be easier to live with as you probably don't have to position the couplings so accurately to get disconnection ( no disrespect implied to the inventor of this modification). Also if you use fiddleyards at all KD's are great because the vehicles do not get hooked up when you try to move them. I am sure you will appreciate all this when you get to have a play with them.