I put mine up on my work bench to get the lines right. Try to make the curve on the top of the deflector line up with the curve of the bodywork. I held mine in place several times to get the idea of position in my head first. I got the position I was happy with and then marked the pannel with a dry wipe white board marker. They both ended up looking great. Don't do what I did the next day though. On a trip from Birmingham to Aberystwyth we called in to a steam engine show and whilst parking on wet grass I put the bike down and broke the bottom of the right side one!