Thought I'd comment because this may be a lower cost method:
Lua Code:
FocusFrame:UnregisterEvent("UNIT_AURA")
hooksecurefunc(FocusFrame, "SetSmallSize", function(self)
self.maxBuffs = 0
self.maxDebuffs = 0
end)
I believe SetSmallSize is the function that establishes the buff/debuff limits, so this should be a one time setup.