Welding script not accurately welding parts?

I need to have an unanchored model with multiple parts that I cant union so I have this to weld them together, it works but the parts welded are always in slightly different places making it look weird.

local weldTo = script.Parent:FindFirstChild('Plane')
local weldToCf = weldTo.CFrame:inverse()

local parts = {weldTo}

function Weld(parent)
    for _,v in pairs(parent:GetChildren()) do
        if (v:IsA("BasePart") and v ~= weldTo) then
            local w = Instance.new("Weld")
            w.Name = "PlaneWeld"
            w.Part0 = weldTo
            w.Part1 = v
            w.C0 = weldToCf
            w.C1 = v.CFrame:inverse()
            w.Parent = weldTo
            table.insert(parts, v)
        end
        Weld(v)
    end
end

Weld(script.Parent)

for _,v in pairs(parts) do
    v.Anchored = false
end

script:Destroy()