The plans make a thing of making templates using a bit of paper or cardboard behind the wheels and noting where the tire and strut are. These get transfered to the pants to make cutting for all the fitting easier.
Well I could almost have skipped this step. When I started cutting it still took forever. We might consider these 'guidelines'. You'd be very brave to just hack away at the pants after using these marks and expect it all to turn out well. You'd be close but we are talking small margin between pant, strut and tire.