[Joeztech]

A closer look at the pin-outs of the two tube types revealed that they are quite different:
7H7                              6SG7
1 & 8   Filaments        2 & 7
  7        Cathode             5
  6           G1                   4
  3           G2                   6
  4           G3                3 & 5
  2          Plate                8

G3 and Cathode are tied together in the 6SG7 but that won't matter much. In the 7H7, G3 is tied to ground externally. With the 7H7 the 68 ohm cathode resistor is not bypassed. With the 6SG7 it might be good to bypass the 68 ohm cathode resistor and G3, but may not be necessary. I will try leaving the cathode resistor un-bypassed first and if there is a problem I can always add a bypass capacitor.

So the layout of leads will be a bit different, but not a significant issue to deal with. There are two ground lances to utilize and I have plenty of wire and parts available.

The radio should not really care as far as gain is concerned since both tube types have identical gain at the same B+ voltage range.

I will do an updated schematic and leave it in an envelope inside the cabinet plus do an updated tube lay-out label to place inside the cabinet too. The 2nd IF appears to work OK so I will leave it as it is.

Joe