The Y7 was done in FUD. The laser sintered nylon can't produce detail or dimensions accurately enough for small scales - i only allowed WSF printing for my models in 1/24 and bigger, basically because the price was enormous in other materials.
Agreed - i made fittings from my NG designs available separately to help people. I started by designing one small bagnall, then realised that the manufacturers had used the exact same cylinders, smokebox door, chimney, steam turret/safety valves, reverser, backhead, tank fillers etc on several designs, so I made a few more - for example all the steam locos at groudle glen (240t, 042t, 040st) are essentially the same parts and fittings rearranged, and there were other variations on that theme built for elsewhere. There wasn't really a source of 7mm, 1/32 or 1/24 small bagnall, couillet or O&K fittings, which had previously frustrated me when scratchbuilding, so I sprued them up and made them available. They certainly turn out better than many commercial white metal castings I've had.