"Note that in my experience, one or another of the driver pair often fails and takes the outputs with it, or the outputs fail and take a driver-or-two."

That is the reason for the procedure I described.

The 2N3773 is better in another way, the gain curve. The 3773 still has 35 HFE at 10 amps, while a 3055 drops to 10. At 5 amps the 3773 is 60 and the 3055 is 30. Both of them start around 100 or so at like a half amp.

"Yes, that HK Series is worth the trouble. "

Absolutely, but I recommend speaker fuses. One good trick to keep the fuses form introducing distortion at high level low frequencies (this is not audiopholery, it is measurable) is to make a high value bipolar out of like 2 8,200 uFs in series +to+ and put it across the fuse. That only DC or very low frequencies will blow it. For this amp all you would need is 35 volt units.