Send her down :D I like a challenge!
I teach my lot to quarter (off lead) by running with them, sending them ahead and then when they get to a set distance , turn them on the whistle. By this time, I have already turned and am heading back in the opposite direction. When training always do it into the wind.
You can teach quartering patterns/turn whistles on any field.It doesn't have to have game on it. I personally, would treat hunting, stop/sit whistle and for you flushing/for me pointing as three separate exercises and only combine them when I am sure that the dog will obey a stop/sit whistle.
I can't remember where we got our tracking leads from, but they are 20 foot long and just like a normal lead. They are very strong cotton.
I will try to remember for you

Leigh xx