[Arran]

I wonder if all versions of these had the same lousy band spread on short wave? Note how it goes from 5.5 to 18 mc on a single band, pretty much like the non Teledial Grunow that Bob Andersen has. In spite of this they used a sweep hand for logging, which seems almost like a waste of time. On my G.E M-83 they used five bands, longwave, broadcast, and three shortwave bands.
With regard to using 6F6s or 6L6 tubes as final outputs, that could be because of marketing, or simply because G.H.U managed to get a deal on 6L6 tubes in bulk. Apparently this was done with one of the brand Z models, they fitted the set with 6L6 outputs for marketing purposes, just to make it look like an audio "Hot Rod", but the 6L6s didn't do very much since the power supply didn't give them the extra B+ voltage they needed, just the usual 225-250 volts.
Regards
Arran