Anyways, I use the trainer button for brakes..easy to get at (sliders are a royal pain when you are still trying to fly the plane...), and can be pulsed with your thumb..
That's what I wanted to do after getting my 9303 until I discovered that I couldn't prevent it from turning my timer off and on. It is not possible to decouple the button from the timer. I believe JR has made a software programing error. It seems to me that when you assign another function to the button that it should disable it from the timer - not so. You can also operate the timer from the touchscreen.
For me it just makes it a hassle if I use brakes taxiing out to make sure the timer is on for take off. I am now use to using the right slider for brakes and that works fine, especially with proportional brakes.
Joe