Without paying alot of money, the hammond is the best way to go. But I have taken power transformers out of junker sets and used them successfully. I just did a GE L-916 and replaced it with a Stromberg Carlson model.
One thing to keep in mind in the orientation of the transformer. Usually the PT was situated “side down” and the output transformer was upright and at 45 degree angle to prevent magnetic coupling that will get hum into the audio. If you replace it with one that is upright like the output transformer, you may get this unwanted coupling. Something to keep in mind.