Admittedly - I just looked at the technical data for the transformers, e.g. https://airlinktransformers.com/prod...ange-cm0750255 ... which you really would think that they'd replicate that most basic of info. Even on the link you provided there's no clear statement as to the phasing of the windings (I've seen better data sheets).

Edit: Actually, I take that back. The link you provide does, in the schematic symbol, give the phase relationship of the tails.