I did too when we did the mini-tub. I traced the edge of the stainless trim with a scratch awl, and then removed the trim. I took a cut off wheel and trimmed along the scribed line. Finished the edge with a grinder.
If done poorly or incorrectly the baseball bat method can cause the quarter panel to bulge out instead of being straight. This is really obvious on a black car like mine. And you'd better hope there isn't any bondo in those quarters over the wheel wells if you plan on rolling them... :oops: