You don't need a specific ini. What you have to do is to put the adjusted timings into a crt_range that only applies to the desired vertical resolution range, e.g.:
crt_range0 15625-16200, 49.50-65.00, 2.000, 4.700, 8.000, 0.064, 0.192, 1.024, 0, 0, 192, 239, 448, 576
crt_range1 15625-16200, 49.50-65.00, 2.000, 4.700, 8.000, 0.064, 0.192, 1.024, 0, 0, 240, 240, 448, 576
crt_range2 15625-16200, 49.50-65.00, 2.000, 4.700, 8.000, 0.064, 0.192, 1.024, 0, 0, 241, 288, 448, 576
Above, crt_range1 is where you'll put your ajusted timings. Because you define the progressive lines min and max as 240 it will only apply to that vertical resolution.