I agree with jea48, and I will add something about solid wire that I do. First, if you are not going to use this idea, that's fine but don't forget to slightly retighten the screws, since the copper wire will compress ever so slightly when screw pressure is applied. You won't get more than 1/16 of a turn.
My idea of getting a bit more surface contact is to carefully flatten the copper wire after shaping it for the side screw connector. I do this by using a device that applies pressure squarely to the conductor. Not pliers, because the jaws are not parallel when they clamp. More like a small vise that will flatten the conductor just a bit. Then the wire can be fitted to the screw terminal and tightened as stated above. Sometimes I will use a conducting enhancer, but it mostly for protection from corrosion.
My idea of getting a bit more surface contact is to carefully flatten the copper wire after shaping it for the side screw connector. I do this by using a device that applies pressure squarely to the conductor. Not pliers, because the jaws are not parallel when they clamp. More like a small vise that will flatten the conductor just a bit. Then the wire can be fitted to the screw terminal and tightened as stated above. Sometimes I will use a conducting enhancer, but it mostly for protection from corrosion.