Same principles apply....flyers used in lower 3 bases ideally. The wall spacing keeps enemy heroes close to hero bases so ranged can attack without wall hopping unless* your garrisons are high for magic towers. It could lead to a stun lock and a ground ranged hero hopping over. I added some pathing with the extra walls to the top entrance which was the weakest part of the base, as well as a stagger concept with spare walls to the front entrance....this has helped greatly in minimizing AC procs (can't recall one but I won't guarantee it'll never happen).
I still farm Hbm R, except now ungarrisonned. Hero bases and towers are still lvl 20. Only my TH and Gold Vaults have been upgraded.
If you choose to farm Hbm r ungarrisonned i suggest using arrow towers for higher hit point pools. I leave arrow towers because I garrison them for easy Hero trial wins and don't like swapping back and forth. Fortunately, my heroes are skilled enough to be able to handle R with the weaker magic towers.
As always, everyone may have mixed results, but here it is.....my base with level 21 TH.