Found rugged linear stage with sufficient travel to cover all welds.
Mounted heavy steel angle as table.
Made phenolic cell supports.
Made weld actuator and weld jaws.
Not going to work reliability due to movable side contact not making good contact.
The most positive battery electrode will not make contact with the movable electrode, so this fixture cannot do that weld.
Will save these jaws for future reference and try a different approach.