nope, honestly dont think so. its just not the same jumping on a wide object while you are stationary. there are so many other factors that come into play when on park features it is not even worth it to try and "practice" on whatever you have lying around the house.
If you don't like the way I drive, stay off the sidewalk.
I just got a mm deep scratch that is along the length of my board.
Is this going to affect how it rides?
Do as Riley said and take a razor blade and remove anything sticking up from the scratch and make it flat with the base. Since the scratch is lengthwise you should have no problems and a good waxing should take care of the rest.