NMow, that's a REALLY creative and original mod
I'd SWAG that this should also work with a UX-7 socket, as they are the same diameter. Maybe even locktal sockets if one wants to go that route with 7C5s or 14C5s (the 6V6GT & 12V6GT equivalents) - that would be more difficult with the center tube socket, too many etches which shouldn't be cut, so no 7F7s or 14F7s, sorry 'bout that, Chief....
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With the drilled out boards and UX-5 sockets, you might want to use a 1K resistor as the "jumper" for the control grid, keeps the grid stopper closer to the socket, that way.
The other "hack" that I had thought of was to wire-jumper to 9 pin sockets, for all three tubes, and then use a 12AX7 or 12AT7 / 12DT8 driver and two 12B4A outputs, and otherwise exactly duplicate the 1626 circuitry and voltages. That would deliver about 1.5W vs 0.75 for the 1626s.
I've already proven out this concept in a P2P wired 12AT7/12DT8 & 12B4A SET earlier in the year.
Now a REALLY
cool rev B Clementine II board could have the two outer sockets set up for both octal and 9 pinners, as with the VA stage in the "Ike" second rev board.
/ed B