Wondering if I can grind the flex plate hole a bit?

 

Nope, just unbolt the ones you already have in, and rotate the t/c 90 degrees, see if all the bolts line up. If they don't, take 'em all out, rotate another 90. It only bolts up one way. It MUST be bolted up correctly, or you will have balance issues, and a vibration that will destroy both the engine, and the trans.