Say you start with a 208Y/120V source limited to 100A (36 kVA). I'd be interested to see the math on the largest 2-wire 120V load you could serve via a Scott-T transformer that makes 170V/120V 2P5W (not sure if that voltage nomenclature is standard, those are the two different L-L voltages).
For common transformer arrangements, the best case would be to use a 208V : 120V single phase transformer, that would let you supply a 173A 120V load. If I'm not mistaken, that matches using a Scott-T transformer to make 120V/85V 2P4W and supplying the 120V load from the "main" transformer, and it beats using the "teaser" transformer from such an arrangement.
For uncommon transformer arrangements, I believe the best case would be to use (3) 120V:60V transformers, one on each phase, and put the outputs in series to get 120V single phase (60V ∠ 0 + 60V ∠ 60 + 60V ∠ -60 = 120V ∠ 0 ). That would let you supply a 200A 120V load.
Cheers, Wayne