It has been my experience that any plug other than the stock designed ones, will not reduce ignition RFI. It may not be any worse, but it isn't going to magically cure RFI.
Modern engines, especially those with long tune up intervals already use platinum tipped plugs. And I would even agree that some of them have more than one ground electrode. But the truth is, most of the RFI comes from the plug wires themselves.
On COP equipped engines, the majority of the RFI comes from the control wiring. I've tried about everything I can think of, even to the point of making up my own shielded wiring harness, and I can tell you it's almost a waste of time. You MIGHT get the level to fall a few S units, but you'll never make it disappear. Even electronically controlled diesels are getting noisier.
I'm waiting with baited breath for the new Bosch system that incorporates direct fuel injection, ignition, and knock sensor all in one.
Too bad they don't make one model just for us amateurs. They could call it ATV; Amateur Transceiver Vehicle.