Replacing Arnold couplings with Kato ones

I recently aqcuired a rake of Kato Taki 1000 oil tank wagons (set 10-1167) to go with my EH-200, and while they're perfectly decent wagons the default Arnold couples really do stand out and look clunkier than usual. Normally I'm not too bothered by Arnold couplings and can "unsee" them, but these had to go - replaced by the Kato coupler (part number 11-707). Mildly fiddly to assemble and put in place, but they make a huge difference: