I've done my entrance holes several different ways. My first hive had three on the side, and the only thing I didn't like about that is when I stand on the side to work the hive, I'm kind of in the bees' way since it's backed up to a fence. I find I stand on the side more than the front. So the next few I put on the ends. I've read pros and cons about holes on the top or bottom for air flow, heat, etc., so I decided to do a bit of both. I've put three holes vertically on the front of the hive and to the right or left, not the center of the front. Make sense? And they seem to close up the top two in winter, I guess to hold in heat. I figure with three vertically, they can decide if they like top, middle or bottom entrances. I've liked this design really well for the last two years. I just do one-inch holes, but I think I'll try 7/8 so I can use wine corks too.