Even with ideal stand placement getting an old buck within 20 yards of your stand is tough. They don't follow the same trails every time. They can decide to trot through your shooting lane. They can turn towards or away from you as you draw back and not give you a shot. I truly believe that once you get to a certain level of knowledge and skill it comes down to 2 things: time in the stand and luck. From what I have read from you, it seems like you are only a lucky break away from a real monster.