I'm sorry for those of you who don't want to change years of muscle memory, but right-click is more common that middle click and should have the easier gesture; 2-tap for right-click, 3-tap for middle-click. If you are a heavy middle-click user, you should certainly change the settings on your computer to assign the easier gesture to meet your needs, but 2-tap should default to right-click.
I'm sorry for those of you who don't want to change years of muscle memory, but right-click is more common that middle click and should have the easier gesture; 2-tap for right-click, 3-tap for middle-click. If you are a heavy middle-click user, you should certainly change the settings on your computer to assign the easier gesture to meet your needs, but 2-tap should default to right-click.