I'm thinking let the drones hatch, .

You are going to rear mites. One drone brood produces 10 mites.
If you have now 10 mites, you have 1000 mites in September.
Now Finski that was taken a little out of context. What I was saying is what is my most important priority? The drones are already there, let them hatch, There's nothing I can do about it now. Varroa is a part of modern beekeeping but who knows that better than you. I'm saying that my priorities are 1--Make Splits. 2--Get a queen laying in new splits. 3--Treat the varroa with Oxalic Vaporization not once but twice about a week apart. I would rather use the trickle method but the only broodless period I saw was in the late fall. I did use formic acid after summer, mite away quick strips. They worked but the bees paid quite a price. This fall I will be using the trickle method but till then vaporization is all I've got.
If you have some other way I can treat for mites now that the brood is heavy, other than formic acid, I would very much like to know how to do it. Please share. Also, I understand that requeening in the fall also helps to reduce the mite load going into winter by creating a break in the brood cycle. I plan to rear enough queens to do this in all of my colonies. I welcome your advice.