Its a 6-tube set with two active IF amplifying stages at 330 kc utilizing then then 'new' screened-grid tubes. Regeneration is applied at the detector.
This photo shows one of the tuned IF assemblies.
Here's a photo during bench testing and alignment
This is the completed radio including a box to store the many plug-in coils.
The radio remains 'open' so as to have access to the plug-in coils.
Given Mr. Hull's amazing expertise its no surprise that it is a top-notch performer. Not many hams of the era could afford or build a receiver of this calibre but they did indeed exist.