The kiki guy wrote a nice paper. That's especially true for the 1969 date he completed it.
Though he did not emphasize it, his writing supports the conclusion that once the US had New Orleans, Mobile and Savannah under close blockade, the blockade runners were already redirecting towards secondary ports that did not have the labor force to handle cotton and the incoming freight. What the Confederates accomplished using those secondary ports was very helpful to their cause, but it was never 5 million bales per year.
I have yet to encounter a historian who states that the coastal blockade was never a stand alone operation. There was always an intent to control the Mississippi River as far down and possible. Generals Scott and McClellan exchanged correspondence in 1861 agreeing that an attempt to capture New Orleans was a high priority.
The US targeted international imports in the blockade. But it seems to me that by 1861 NYC was already a major production, distribution and finance center. Any part of the US that was cut off from NYC was going to find prices, availability and credit deeply restricted.
If the labor force on NYC and the surrounding counties became unavailable and all those longshoremen had to be replaced by people in Bermuda or Nassau in the Bahamas, it seems to me that the section forced to make the substitution is already in trouble.
The paper suggests, though it does not explicitly state, that neither the US nor the British wanted a flawless blockade. If some Confederate cotton arrived in NYC or Liverpool that decreased the demand for intervention. Also, if blockade runners could dispose of their inbound freight at outrageous prices, and buy the cotton at a discounted price on the dock, then that would create a pro blockade lobby in London.
By the time in September 1863 that Charleston is also under close blockade, with the port essentially sealed off for about 6 months, its too late for the anti-blockade to do anything. By that time the EP is in force. Benjamin had closed the Confederate mission to Britain. Britain was interposing the exchequer between the British rams and the Confederacy and Admiral Milne was communicating for the British with his US counterparts.
The Confederates probably imported enough rifles and munitions to fight the battles that cost so much blood later in the year.
But I suspect what the smugglers could not afford to carry included rails, plate iron, railroad wheels, and tools of all sorts.
Despite their best efforts the Confederacy was moving backward into the 18th century. That inevitably made them dependent on horses, mules, wagons and caissons, and there was never enough of any of them.
In the end, when the Confederacy was desperately short on caloric intake in its armies, the blockaders were capturing a high per centage of the attempted runs through the blockade.