You can use your own icons, but there is no user interface for it. You just have to put a .jpg file (can be a PNG, but it needs to have the .jpg extension) in the same directory as the POI database, and with the same name as the category for which you want to use a different icon.
There's not a lot of room in that dialog to show more than two lines at a time, but I can try tightening up the dialog a little.
Actually, there is a lower bound on the auto-rotation. You have to have at least some speed in order for the auto-rotation to work. I can provide an option to increase this minimum, if that would help.