The crosshairs should not 'shake', but they will 'flicker'. It's the nature of the beast.
As far as remapping the buttons, you can map it to extra buttons on your mouse, such as X1 and X2, but I would advise against mapping to your standard mouse buttons. There are times and weapons that you will want to use those buttons without the QS.
You can find mapping help in the documentation of AutoHotKey or in thier community forums.