Yes it is a Compur size 00..
Oh. #00. Modern Compur #00 shutters rarely have cable release sockets and there's no easy way to add one. The suggestion in post #4 above will work but attaches to the shutter, not the board. Now that I think if it, one of my paperweights is a thoroughly destroyed (cracked and chipped internal elements) 90/8 Super Angulon in a #00 Synchro Compur, also in poor condition, with cable release socket. The socket is held in place by two screws whose heads are inside the shutter body.
Two other solutions. #00s in some older folders have cable release sockets. Not mine to reason why. Find one, move the lens' cells to it and make an aperture scale to suit the lens. Or have, for example, skgrimes scale the shutter. I've done all this for a couple of lenses.
The Seiko/Seikosha shutters many Topcor lenses for 6x9 Horseman cameras are in also have no cable release sockets. Horseman boards for these lenses have devices that accept a cable release and push the shutter's release lever. Get one, remove the device and attach it to your board.
By the way, which lens is in the problem shutter? I know that selling or tossing a lens isn't a great pleasure but you might be best off simply replacing the lens with one in a shutter with a cable release socket.