My girl is a year old. We are through FF, CC, basic 3 hand casting, and are almsot done with FTP. The problem is, when I stop her going to the pile, she flares like crazy. What is the best way to get rid of this? The checkcord is helping, but soon as I take the cord away, she does it again. Should I keep using the cord, more pressure, less pressure, attrition? I appreciate the help.

Reduce your distance until you have good sits up close and then progress to greater distances.

It has been my experience that slow looping sits are best handled on the tee or double tee's. Here you are casting and are in a total control situtation. If you have forced and collar conditiond you dog give a low burn just before you blow the sit whisle and reinforce with a verbal SIT. He will get the message quickly.
Warren