I don't understand how the 1/2  3A5 regen "didn't work". There's only a half dozen parts. 

This idea dates, i think, from a QST article 1940 or -41. But it used  triode - pentode, with the pentode as the receiver. Also they drove the xmtr to watts, not < 1 watt. 

The CRC-7 rescue radio used the separately energized filament sections for T - R switching and i wonder if that's where Wesco got that idea. 

Many decades ago i assembled a 1 triode 6J5  VLF regen and did get a USN east coast station with it. The radio had as very limited tuning range and there were rather few CW stations on the air. 

-Hue Miller