I have a feeling that the Wintergreen Oil and Lard patties were really targeted for Tracheal mites.
Various mints/menthols mask the smell of bees, and thus diminish T-mite loads.
Using grease patties for T-mites is nothing new, but it is being abandoned because of SHB concerns.
For Oils/Fats to be effective on Varroa, it has to come in physical contact and actually sufficate the mite to be effective.
Some have burned/vaporized various oils in insect foggers to have this effect.
Others swear by using oil soaked cotton cords or just dribbing it on the top bars.
I think that's all a waste of time and money.
If you break your queen's brood cycle (requeen at the right time), you break the mite's mating cycle and population before winter when it counts.
Fat/Beeman can chime in here if he's so inclined. He's had some vidoes (I think using Tea Tree Oil?) online.