First year BK in North Alabama which mite treatment?

So from my understanding I should sample between July and first week of August as that’s the start of the “population decrease” (e.g. when supers come off)?

I have nothing in my super (they were drawing comb it it) but they have effectively stopped drawing comb at this point.

Honeybeehealthcoalition.org

I was following this recommendation guide and it seems I can use Apivar or Apiguard. I’m not sure which I should use. Is there any general recommendations on which to use?

Also I have a couple weaker hives that were splits from when they swarmed that I would like to feed. If I have mite counts that require treatment, both of these seem to be 30+ day type treatments. Will I have enough time to feed the weaker hives enough for winter?