I managed to solve the problem. Much of the code that I copied was needlessly complicated and very difficult for me to understand (probably due to its 2009 release date. Yikes!). I decided to bite the bullet and rewrite the code in a way that I can understand. It's far from perfect, but still more elegant than the previous solution. Here it is, if this helps anyone else.
Lua Code:
local _G = _G
for i = 12, 1, -1 do
local b = _G["MultiBarLeftButton"..i]
local f = i > 1 and "MultiBarLeftButton"..i-1 or "MultiBarLeft"
b:ClearAllPoints()
b:SetPoint("LEFT", f, "RIGHT", 6, 0)
end
MultiBarLeftButton1:ClearAllPoints()
MultiBarLeftButton1:SetPoint("BOTTOMLEFT", "MultiBarBottomLeftButton1", "TOPLEFT", 0, 6)
StanceButton1:ClearAllPoints()
StanceButton1:SetPoint("RIGHT", "MultiBarBottomLeftButton1", "TOPLEFT", -6, 4)