germany TT can have the austrian as premium (only tranche one)
italy TT can have the spanish
uk TT can have the saudi as premium (only tranche 2 and 3)
with the spanish one given that they have all 4 tranches you can have event premium and squadron while not removing anything from italy that also has 4 tranches.
i interpreted your “what nation” as to who can have it, not whose roundel was it.
anyway austria, so that camo if it comes early will be on the german one probably