I agree density has a big part in it. Lower density will def be easier to blend. However another thing u can do, Is what u mentioned above.. about people who have the hair on top.. they can style the system hair in a diff direction or style it etc.. Well i do the same thing sort of but with the piece hair. u can part it sort of.. So that some of the hair is going forward. and the bottom half is going downwards.. that way ur creating ur own distinction of what should be the side hair .. hard to explain.