If you use an A112 water pump, and use an electric fan for the radiator, you can mount the oil cooler in the area where the stock fan/ water pump normally is. I saw a photo of this just recently, but cannot find it now.
Maybe you want to consider an oil thermostat for the oil cooler setup? You should be able to adapt one from another make like VW maybe? The reverse oil flow modification is a good idea I think. You can add a pressurized center main bearing this way if your engine doesn't have it, and you can drill a small hole in the cam bearing to oil the distributor shaft gear.
Gil