If I may, at the primary impedance level that the 32004 transformer represents (7600 ohms plate-to-plate), it is not possible to get anywhere near 50 watts through or out of those transformers, except maybe at mid frequencies only. With respect to producing a flat 20 Hz to 20 kHz power band, about the most these transformers are good for with typical B+ voltages and even EL34 output tubes is 28 watts RMS at 20 Hz. This paring was really a compromised choice to use in the HF-35, as the power band of that amplifier falls off notably on the low end -- again, down to the above mentioned power level from a mid frequency power output of about 34 watts. Of the HF-20/22/35/50/52/60 series of amplifiers, the HF-35 is the only model to have a reduced LF power response.
This is hardly to say that the 32004 is a poor transformer -- in fact, quite the contrary. When used with 6L6 class tubes with cathode bias and a 465 volt B+ supply, they will produce an absolutely flat power band from 20 Hz to 20 kHz, at a maximum power output of 22 watts RMS, and can do so with very low distortion.
The 32007 transformer, as used in the HF-50/52 is also an excellent transformer (lower primary impedance), but requires a bigger power transformer than the HF-20/22 employs to produce the power it is capable of handling. As good as this transformer is however, it is bested by those in the HF-89/A, but even these are not as good as the HF-60's Acrosound TO-330 transformers, which even today remain a standard to be beat.
Dave