Verlaat- Great SS (best out of the 4) Zalzugal- Great SS and also usable with only 1 copy. Allind- Good SS (least useful out of all them) and okay as 1 copy but you want 2. Oseon- No one cares this has a SS and usable with 1 copy. Also you already have Marduk.
That being said I say Oseon but up to you and to your needs.