Yes, we have a regurgitator. It's not a nice problem, particularly because it's hard to break a cat of the habit of eating too fast. And her sister (the one with the microchip feeder) is a very dainty, slow grazer.I'm in a similar position and just ordered the SureFeed. I don't think you can train them. Some cats will only eat a couple of bites then walk away. You don't really want them to gorge as that can bring other issues. Had a couple cats eat too much too fast and regurgitate.
I hope the SureFeed works for you! I've read good things about it.