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Would any of the VIs in \vi.lib\Utility\VariantDataType\VariantType.lvlib help you? You should at least be able to use the GetTypeInfo VI to see what your mystery F1 is.

From a different perspective, can you even do what you want with a arbitrary cluster? That is, go from a cluster directly to an array of variants.

The Variant To Data function can do this. Wire in an array of variants into the type input and a variant representing your cluster into the variant input. See the attached image. This also lets you go from a variant containing an array to an array of variants.