Oh, I thought you used an encapsulated transformer (something like a BLOCK VCM 36/1/12) but I guess that’s pretty much what that is even if they call it “adaptor” 
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(if you go for brand-name transformers, you might as well get a 2x12 V since that usually costs the same, but otoh I’m not sure if you can rewire e.g. the FC PCBs to work with that, so that option might just be for strange people who build their own supplies).