You have a strong PC, a bit stronger than mine. And even a bit more upload speed (I have 0,4). When I had the xsplit licence and I was broadcasting I used these settings:
Broadcasting at 720p 24fps. It wasn't perfect tho and not super enjoyable. I think that if you lower a bit the fps, for example to 15, and you increase the VBV Max bitrate and the VBV buffer, for example to 480 and 960 respectively, you would have a watchable streaming. If it doesn't satisfy you you could try 525p
You also have to set the location server. I suggest you downloading and using the tool here to find the one that is better for you:
http://www.teamliquid.net/forum/viewmessage.php?topic_id=326034
We are working on a guide for streaming anyways, it will be up soon