torque: I've used super glue on just about everything. I probably use it more than duct tape at this point in my life! Most of the time it works very well, but some materials not so much. I see no reason not to try though. If you're using a large amount on the stem it might feel a little harder in the mouth, but you should be able to polish it to match your other material if you're careful.
pruss: I have used it on acrylic stems and it works very well, as it seem to have the same hardness to touch as acrylic. The nice thing about acrylic stems is that if they're the multi colored type, you don't need to color them if you're just filling dents. Because the glue is clear the surrounding colors show through. If they're solid color you might, or might not have to color the super glue depending on how deep they are. Only way to tell is just experimentation. I've never colored super glue other than with black though.
pruss: I have used it on acrylic stems and it works very well, as it seem to have the same hardness to touch as acrylic. The nice thing about acrylic stems is that if they're the multi colored type, you don't need to color them if you're just filling dents. Because the glue is clear the surrounding colors show through. If they're solid color you might, or might not have to color the super glue depending on how deep they are. Only way to tell is just experimentation. I've never colored super glue other than with black though.