pollen substitute, Honey Bee Healthy and Amino B Booster (each at 1 tsp per qt of syrup) to hopefully keep the queen laying for bees of winter physiology to build the colony before cooler weather hits. Will switch to 2:1 sugar-only when it cools down.
I do have an in-hive feeder like the one you linked, just prefer using the top feeder I made (based on the Dave Burns design) for now. They are draining a qt jar every day, but it is easy to just lift the cover and replace the jar. Can actually put two jars on at the same time also. A medium super box covers the jars.
Have the varroa test kit, but will wait a couple weeks to get plenty of new nurse bees before doing the first test.
2nd hive, yeah, already planning on getting the boxes and frames to assemble over the winter to add in the spring. Will be expanding the area on the hill for the hive(s) once we get our winter rains and the decomposed granite soil softens up enough to dig. It is like concrete now at the end of summer.