Reading back through there is one more thing you could try. It sounds like it might be too lean on the low speed and too rich on top. Set the bottom so rich that it really loads up after just a few seconds of idle, just lean enough to stay running on the track. Drive the car and get the high speed dialed in on the straights and get it up to good temps. Then while it is still hot you can try to get the low speed tuned in better.