Sealing transmission pan

Got a simple question. I've used the "LubeLocker" trans pan gaskets on a pair of 727's and the pans still leak. The avatar's leak I attribute to the cheapo chrome deep pan on it. Can't recall if I scuffed it up a bit before installing but regardless, that pan is coming off and a new gasket installed with a different pan.

I got this standard depth pan from Summit for my other Demon. It's a show pony only car so it doesn't really need a deep pan. My question is do you typically take some sandpaper and scuff this type up a bit too? I'm going to try the Summit brand pan gasket on it without any sealant and see how it does but was first interested in what others do. Thx!
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