Hi Jim,
I didn;t see your post until now.
PT-6 pinout:
Terminals are bunched up toward the right on both back and front rows.
Back row from left to right - 7,8, small gap, 10,11,12 closer together than front row terminals
Front row from left to right 18,17 a little bit bigger gap than the back, then 15,14,13.
OT-2 pinout:
With channel frame flanges on bench,
bottom row from right to left is 1,2,3, then 4 has no terminal, then 5 at the left end
top row from right to left is 6,7,8 then 9 has no terminal, then 10 at the left end
As to extra terminal pads on the power supply PC board, if you check along one long edge of the board you will find a group of three pads close together about three quarters of an inch in from each end. Those are all B+ pads and the outermost ones are extra. At the center of that same edge is the ground and just outboard in each direction about a quarter of an inch is each cathode connection. Those are all going to have wires in them, there aren't really any extra pads for cathode bypass caps. The cathode caps are mounted directly back from that edge, between the cathode pads and the B+ pads