Front fender trimming question.

What size tires are you running with what back space ?

My front wheels are a little too tall and catch the bottom of the front fender when turning, right where it comes to a point. I would like to trim 1/2 inch back to make it work and have room to spare. What is the reccomended method of doing that? I was thinking of taping off a line and using a cutting wheel so as not to damage the paint job.

thanks