what size should a top entrance be and if using a top entrance would a screened bottom board still be used? or recomended?
Mine are all 1/4" to 3/8" tall and run the width of the hive... well minus whatever the width of the shims are... in the winter I reduce them down to about 2 to 2 1/2". You can use a screened bottom board if you like. Just block the entrance and I'd still put in the tray in winter.