You will always have temp variances within your living space, just a nature of the way these work. The follow-me will use a temp sensor in the remote. I find it doesn't make much difference actually.
The room temp sensor is the black antenna thingie behind the cover that sits just above the cooling coil in the air handler. It's going to sense room temp as the air is drawn into the blower cage.
One of the issues I have with my main 2-ton unit is that it's nearly 10' up the wall with 18' ceilings, so there air is always much warmer up there. We don't have to set the temp control as low to get a comfortable room temp at floor level. The cooler air does sink, it's coolest at the floor - and with all tile floors over concrete slab, if the house is kept cool over several days the floor acts as a heat-sink, or I should say 'cool-sink'.
With a central system your thermostat is in a central location and ducting is adjusted for airflow to balance throughout the home. They are still notorious for areas or rooms that are too hot or too cold.
My next hvac project is likely to be a split double-head unit, the new DIY 18K btu has two 9K heads, for the two back bedrooms of the house. What a great solution.
We'll end up with the whole house done for about five thousand - a third of what the contractors wanted for a new central system. We retained our old gas furnace for our mild winters, the forty year old unit still works like a champ.
The top border of the wall coverings here is 8 feet. It is a real ****** to get that bigger air handler up a ladder and the lineset fed into the hole, and get it hung on the mounting bracket. I sweat like a pig. LOL I've done it twice now, and removed once. Dear lord.
LOL, I love it! My new tag line.