Describe an upper entrance for me. I assumed that once the supers were put on for honey production that I would put a queen excluder below the super and leave it in indefinately. From some of your discussions it sounds like there is some management of the queen excluder. Please describe this.
There are many variations of an upper entrance. A lot of inner covers come with a notch in them. You can slide the top cover forward and the bees can get in and out of this. The notch can be left up or down. If it's up the bees will go out the hole in the inner cover and out the notch. If it's down they will go right off the top bars out the hole.
An Imirie shim can be used for a top entrance, but there will be a bit more burr comb.
A DE conversion kit has a toggle like you see on double screen boards so you can open or close the top entrance.
Bjorn just drills a hole in every box and uses corks to stop them when he wants. Some people drill a hole in the bottom super or the top super so that there is an entrance above the excluder to cut down on traffic in the brood nest.
Where you put your top entrance is a bit dependant on what you want to create for ventilation. If you need more then a hole at the top is better.
I'm now taking a migratory cover and putting 1/4" spacer on the bottom of it on three sides leving one side open for the entrance. Then you can turn the hive 90 degrees. I'm closing all my bottom entrances. I'll let you know how it works out.