19" in mine too, no problems. After you've got it set up where it's going to live, degaussing shouldn't be a problem unless you bring a magnet nearby, or you move the screen while it's switched on. Mine rotates so that's every time it's in use, but I just cut the power to the screen for a second, it auto-degausses and I'm away.
Obviously you're happy with how the mounting itself will function, and no parts will be under long-term stress from the weight of the tube. Can't go wrong!