If you decide to drill it and need help keeping it centered here is a cheap way to center a drilled hole on round tubing using an electrical ground clamp for pipe. Just remove the screw and size the bit to match the hole in the ground clamp, you can always enlarge later if needed. The hole in the ground clamp is barely 1/4". By matching the size of the hole the bit will stay centered and the tall shoulder on the clamp will keep it straight. In the photo I am drilling 3/4" tubing on a drill press but if you buy a 1/2" ground clamp it should tighten down enough and a hand drill will work fine. Not knowing the thickness of the metal you are working with there may be a chance that drilling the additional holes will weaken it.