Don't go cheap on a vaporizer. I would go with the InstantVap 18V Lite Unit. Lorobees has great customer service. If it saves 2 colonies, it paid for itself. If you plan on doing a lot of hives, I use the original 18V InstantVap. Whatever you get make sure it holds 4 grams of OA. You ABSOLUTELY need a respirator. A 3M respirator with ABE cartridges you can pick up at Lowes.
As of Feb. 2021, OA is EPA approved with honey supers on. With a high mite count you can treat on a Friday / Monday schedule for 3 weeks. This way it kills most of the mites as brood emerges for 1 brood cycle. After treatment do a mite wash to make sure the treatment worked.