Bottom hole assemblies for cutting windows in wellbore casing comprise a window mill, a first upper mill, a second upper mill, and a third upper mill. The first mill has an outer diameter that is smaller than the outer diameters of the window mill and the second and third upper mills. The first upper mill is disposed above the window mill at a distance measuring approximately twenty to thirty-seven percent of the distance measured from the window mill to the third upper mill. The second upper mill is disposed above the window mill at a distance measuring approximately fifty-five to seventy-five percent of the distance measured from the window mill to the third upper mill. The third upper mill is disposed above the window mill at a distance measuring approximately one-hundred twenty to one-hundred thirty percent of the length of a ramp of a whipstock for guiding the mills.