Ok heres the trick i learn from a CAL friend, first find your ingame resolution for example
1900X1200
now type cl_dynamiccrosshair 0 so when you run it does move and its good for long distance shooting
Next type cl_crosshairscale 1200, this number will the the width of the resolution. 640X480 cl_crosshairscale 480, you know, i use that, but pros tend to choose thier own, i found this usefull the crosshair size if perfect for spraying and long range