I actually made some screened inner covers and put them on the hives (along with SBB's for each). I had so many issues with robbing last year I am planning on keeping my entrances reduced all year. Might change that. But should have plenty of ventilation between the screened inner covers and the SBB.You might/should remove the entrance reducers on your hives during the last couple of 80 degree days. Mine were fanning and I don;t have any restrictions on the entrances. assuming you hives are pretty full of bees.
Best part about having bees in your back yard - you can check them everyday all dayPears, apples, cherries, dandelions, and all sorts of things unseen. Don't get in a rush. The flow will come. Be prepared for it.