I finally tested all four cells individually.
The first three cells I tested at 10a
The final cell I tested at 20a
My tester was set to cut off at 2.3v, which would mean about 2.5v at the cell.
My cables for cells 1 and 2 were a bit thinner than I'm comfortable with. My cables for cells 3 and 4 were quite good, usually around 0.05v drop from cell to terminals of the tester. So not entirely comparing all apples with apples TBH, but I had wanted to assemble better cables and see what difference it would make.
My photos are not always as the test completed so sometimes the cell has recovered a little bit of voltage. I also sometimes dropped the amps right at the end to see out of curiosity how long the test would go on for. Because the amps got quite low even if the test went on for a few minutes very little was added to the AH (to be expected).
Cell 1 - tried very low amps at end for a while which added about 1ah to the total
Cell 2 - usually hits low voltage first so surprised it's higher than cell 3
Cell 3, wasn't expecting it to lower than cell 2
Cell 4 was the best, but usually ends an assembled battery test at highest voltage. Wh are slightly lower than cell 3 though.