[PyMOL] sticks with different radii

Hi, I would like to use different stick radii for the backbone and side chains (e.g. thicker sticks for BB and thinner ones for SC). The command "set stick_radius=X" seems to set the global stick radius, so I cannot use this command to set different radii values for different selections. Does an

[PyMOL] moving one segment relative to the rest

n purpose. Thanks. Shohei Koide