Ignition Coil

Hi all. This is my first post. I have a Kohller Command CH 20 engine. This engine is on my welder I inherited. Long story short, I thought the engine was seized but it turns out that the ignition coil was seized to the flywheel so when I hit the starter, it snapped on of the ignition coil mounting brackets off. I had a guy remove the old coil and weld the two leg mounts back on. He did a good job BUT the gap is too far after any adjustment "play" in the ignition coil mounting holes. I need about 1/2 a hole more to have perfect timing. My question: can I drill a half moon hole adjacent to and within the factory drilled hole? Will this cause any issues? This hole will not conflict with the pins holding the outer coil together and I wouldn't think affect much surface space at all. Recommendations? I attached a picture and am talking about drilling just about where the "R" is in the word HERE!