Adaptive: cFos/cFosSpeed will adapt to your connection automatically. Use this setting only if you are not sure what your connection type is. Otherwise, select the setting that applies to your connection. The better the chosen setting fits your connection type, the lower ping times should be.
Clear the traffic shaping data by clicking on "clear calibration data"
Make a short full-speed download. (5-10 seconds)
Make a longer full-speed upload (30 sec - 1 min). It is important that this upload is as fast as possible, i.e., that the server you're sending to is near and powerful (like your mail server or some fast FTP server). moreover, it is important that you have no downloads running while you do this upload. with an upstream of 256 kbit/s you need to send some 2 mbyte to the other side.
That's it. The connection is well calibrated if you have a full-blast upload and still have low ping times (both can be watched in the status window).