You can do this in SGP. You'll need the Image Statistics window open. Connect the camera and cool it to your desired temperature. Once cooled, cover the camera opening and take a bias frame, or simple take a frame and focus exposure at 0 seconds. Look at the mean value in the Image Statistics window. You want that value to be between 500 and 1000. To adjust, click on the tools icon for the camera and adjust the offset. If the mean is below 500, adjust the offset up, and vice versa if the mean is above 1000. Keep taking images and adjusting until you get it set.
Once that is done, take the cap off of the camera and point it at a brightly lit wall and take a 5 second or so exposure. The idea here is to fully saturate the sensor. Look at the Image Statistics window and note the mean. You want that number to be between 60,000 and 65,535. If it is less than 60,000, turn the gain up, and if it is 65,535 (it will never be higher), turn the gain down. I like to shoot for about 63,000.
Once you have it set, check the offset again to make sure it hasn't changed. If it has, repeat both steps.
Once you have them set, you never need to chance them.
Tim