probably depends on the circuit,
if you have a cap feeding the OPT then it is easier on the transformer,
current handling, flux and unbalanced DC are the tings you might want to look at,
how much voltage you are swinging on your output amp, most inputs use a nickel alloy core so you have to watch out or saturation,
the turns count and size of the core will determine how much DC imbalance the transformer will tolerate,
wire size can be a problem, #46 is rated at 2.5 ma, so you would not want an SE amp with 10 ma driving that,
a lower ratio transformer will have bigger wire as there is more room on the core and they like to keep DCR down so they us as big of wire as possible.