Where did I say he was wrong? I said it's not surprising that laying a cable across an uneven surface is going to not match your estimate, especially back then when we didn't have fancy, detailed undersea maps like we do today.
OP said the cable lengths were consistent with a globe, not that they were exact to the centimetre. I would also guess that cables laid now days are MUCH closer to estimated lengths than your example from 60 years ago.
Regardless, the distances all work on a globe map, but can't be fit to a FE map which is the OPs point.
I really just see speculation about sea floors and unjustified statements that lengths were fed out that exactly matches an RE.
What I see is the idea that...
1. We know the approximate length of undersea cables.
2. These lengths match a globe map.
Seems justified to me, after spot checking the lengths and measuring on a globe.
You said: "Doesn't look too exact to me. The segment runs for the Transatlantic cable required many miles of extra cable"
From your Wiki: "Total amount of cable paid out, 949 miles; total amount run by observation, 818 miles; ... Surplus cable paid out over distance run by observation, 131 miles "
What they are saying is they traveled 818 miles and paid out 949 miles of cable, which is exactly what you would expect when laying cable over underwater mountain ranges. Why is this a problem? Do you not believe there are underwater hills and mountains?
If you take the length of any undersea cable and then find the distance between the endpoints on a map, they always match within a reasonable margin of error. You never see a cable that,s supposed to be 2,000km long and measure 8,000km on the map. The point of the OP is these cables all are roughly how long they should be on a globe Earth.