I keep revisiting this gmail thing every month hoping there is a good solution but U keep running into the same issue. By turning off recent mode it fixed one problem with the sent mail. I don't get mail sent my the iphone. But, I will get mail sent by the web app. I usually use the web app at home or at work sometimes and usually its to chat with someone, so there are threads that can be huge. If i am doing it via the web app then all my sent msgs along with the ones I receive end up on the iphone.