Seems ok, just a couple of things you may want to think about.
The buttons look slightly too far apart to me, you may want to do a simple mock up of the button placements to see how easy on the hand they are.
Also the spinner may get in the way of the trackball. You may want to move it further up or to the left.
Just my $0.02
Im in the process of designing a 2P CP myself at the moment. It has a trackball but no spinner. My design is also in the very early stages and is likely to change.
You may want to open the attachment as the lines dont show properly when it is just displayed in the thread. Dont want to hog your thread but if you want there is more info about my CP
here