That's the problem you wont find any because he didn't try , Cant you see that's George McClellan to a tee and that's why he's such a poor field commander even Bragg , Hood , Burnside all considered poor Army commanders risked all to achieve a result and that's what War is about the element of Risk has to be there in order to gain something out of a huge loss of life.Then show me an opportunity he missed. Show me somewhere he had a chance and did not take it, somewhere a good field commander would have done something else.
Bonus points if you can show me one where the information was actually available at the time, but it's not required.
Lee , Grant , Are considered the best commanders of the war because they took huge RISK'S even Forrest took risks in attacking overwhelming numbers to achieve an outcome.
George McClellan on the other hand did not take RISK'S and that is why you will not find any instance of George McClellan having that chance you talk about.
Like I said before Oak Grove and the small actions before that were all small scale operations , Old George was 4 miles away from the attack at Oak grove , He stopped the attack then ordered the troops back to their starting position and restarted the attack again suppose that makes sense?.
Risk and George McClellan are like chalk and cheese.