WoWInterface - Debuff Skinning

As many of you may know, the wow code uses an overlay for debuffs that controls the color its border is. This border is really ugly. I wanted to reskin this border and wrote the following:

Lua Code:

local debuffSkinFrame = CreateFrame('Frame', nil, UIParent)
debuffSkinFrame:RegisterUnitEvent('UNIT_AURA', 'player')
debuffSkinFrame:SetScript('OnEvent', function(self, event, ...)
    for i = 1, 40 do
        local name, _, _, debuffType = UnitAura('player', i, 'HARMFUL')
        if not name then break end
        
        local debuffSlot = _G['DebuffButton'..i]
        if debuffSlot then _G['DebuffButton'..i..'Border']:Hide() end
        local overlay = debuffSlot:CreateTexture(nil, 'OVERLAY')
        overlay:SetTexture([[Interface\AddOns\oUF_Terenna\Overlaytexture.tga]])
        overlay:SetAllPoints()
        
        local color
        if debuffType then
            color = DebuffTypeColor[debuffType]
        else
            color = DebuffTypeColor['none']
        end
        
        overlay:SetVertexColor(color.r, color.g, color.b)
    end
end)

This works beautifully. However, I wonder how efficient this method is? If there's a more CPU or memory efficient way to do this, I'd greatly appreciate it.