Friends don't let friends get rotors "cut". There are white papers on this. If they are truly "warped" (which is rarely the case), they need to be replaced. However, pulsating brakes are usually from uneven pad transfer that can be knocked off with a wire wheel and a light touch. If the rotors are worn close to minimum thickness, I'd get one of the brake kits offered by vendors on this forum and swap them in the driveway. Or at the least if you are not able, take that kit to a reputable shop. Remember, the mass of the rotor is a part of the brake system used to dissipate heat. Lowering that mass is not best practice.
-former mechanic/sole proprietor-