On track I like to shift around 6200 unless I am winding it out like at Sebring where if I shift up a hear I would have to shift right back, but even then I don't like to go above 6500.
That doesn't answer your question though. Do a few pulls in 3rd and 4th and feel when it comes alive, around 4000+? 4500? As long as you don't shift in such a way the you are below 4000/4500 in the new gear, you should be in the power band and liking the performance
6000/6200 has been working for me and is not too hard on the engine. On the street I shift around 3000