I just de-rimmed a 60 gallon tank last Saturday with one hand working at 75% (recovering from an elbow dislocation). All I used was the utility knife and a small Swiss Army knife. I guess I was lucky because it the silicon used on it was a tad thicker than usual. So I only needed to use some strength pushing the knife into 1 corner. After that it was like peeling an apple. I did spend some time to scrape off the silicon residue, that's were the Swiss knife came in.
But I agree with creekbottom, wait 'til your hands are healed... at least when your full arm isn't sore anymore.