RE: Letting Does Walk
In Iowa, during the 2006-2007 seasons, 60% of the deer shot were does. That is one reason why we have big bucks here. I always have a doe tag and reserve the any sex (antler) tag just in case.
If you are willing to shoot does, you are more likely to let little bucks pass. (Next year they may be big bucks.)
I got my doe this year and my antler tag went unused. It was a great hunt.