How to make texture look same scale on side of the cylinder as on it's top?
Many things can reduce the side texture distortion.
The easiest thing to try would be to apply scale. (Go to object mode, Object > apply > scale.)
If this doesn't work though, another thing to try would be to select all of the faces in edit mode, and scale it along an axis in the image editor, so that it "undistorts" the texture on the side.
As this would pretty much ruin the effects of the Smart UV project if you are using that to unwrap. It would be a last resort.