After it cured, I used sanding tools to trim the patch back to its original shape. Or in other words I made the hole the same size as it was.
But now I wanted to know what my clearance is to the tire so I could see why this might have cracked. So I took it to the airport and tried it. I had only 1/2 inch of clearance at the aft end. Not enough. So I checked my left wheel pant to see what its clearance is.