I use the HotShot all the time and swear by it. It will get rid of most all the mites within 2 days. But I don't like using it too close to harvest. I've read articles that says that plants can't absorb the chemical that they release but I don't trust a lot of the research now a days.
If you harvest know you will have to dunk the buds into something or while drying the mites will consume the buds.
Its a hard choice with no real clear answers, but in your case being so close to harvest I think I'd hang a HotShot in both the flower room and when you hang to dry.