With all I've read, trickle method seems to be preferred over vaporizing... maybe because it's easier don't know... I am going to do the hive later this week. I still see some pale varroa on the sticky board... some brood is still emerging. I would think this late that brood rearing is very low.
You mentioned vaporizing in the spring... it's my understanding varroa counts and mite reproduction is at it's lowest point in the spring and not until August/September does the mite count tend to explode... that's why I thought is was best to treat just before the winter to knock down the varroa so the bees go into winter with lower counts. Without brood or drones the varroa don't reproduce again until brood raising starts. I know that all this is dependent on where you are located, the climate and environment where the bees are kept. I'm new at this, that is why I'm asking questions and reading as much as I can.. at least I'm not charging into something totally blind... I hope.. :) But if you have gone treatment free, you must have done something right... There seems to be no one right way and that is what is puzzling... John