David,
I think you have already answered your own question. If other people are running the
oil cooler in front of the radiator and are not overheating, why go off course and experiment with this internal device? I have to admit that I'm not well versed in various type of radiators out there, but most internal coolers I've seen are made to cool the auto trannys, and have smaller diameter tubes than one would see on an engine
oil cooler. I may be dead wrong here, but it looks like you would have to have a custom cooler/radiator made for this application..... which may not be more efficient than going the other tried and proven route.