While perusing the board, I have come across a common theme: that what the Confederacy does, is able to do, and how long it, and the institution of slavery last all hinge on the manner in which the Confederacy receives independence. Now my question for the board is, in your opinion, when would be the best time for the Confederacy to win the war; that is, which way of winning would leave her at the strongest possible position externally and internally, or what win allows the Confederacy to survive, but weakens slavery enough to allow its speediest abolition.
What I am striving for a future timeline of mine is either a Confederacy that includes the Eleven states that seceded plus Arizona territory, or one that contains the only the eleven but where the Confederacy wins by creating CSCT regiments.
In 1908 in British controlled Zanzibar, slavery was outlawed for any person born in 1908 or later. This act would not have ended slavery in Zanzibar until the 1970's, so it is a bit of a myth that the CSA would have to give up slaves now. For your TL, you might want to look at some better diplomatic performance by the CSA. For example, the CSA agrees in its constitution to end slavery with compensation for all person born 10 years AFTER the conclusions of a peace treaty with the USA. Have this done with in the frame of an diplomatic effort to get the UK to at least recognize the CSA. Not intervene necessary, but at least be more pro-CSA.
Next deal with the blockade. The CSA had many sailors and captains of ships but not many ships. This is because the officers sailed their ships to union harbors, resigned their commissions, and traveled to the South. A few ways to get around this problem, such as
1) The ships captained by CSA members sail their ships to CSA ports, then send the yankee sailors home.
2) Move many of the ships to the state control leading up to the war, where each state maintains it own coastal Navy
3) Or maybe some president before the war decides to base most of the American Navy in a port such as New Orleans, so the ships simply fall into CSA hands.
Any of these POD allow a few benefits.
1) The CSA is not blockade, so it logistics is much better.
2) It can export cotton, so it finances are better.
3) Maybe the CSA can even bring in European mercenaries.
4) The CSA can do amphibious operations against the north. Major operations like taking New York are not likely, but taking things such as Martha Vineyard are possible with control of the seas. A few troops raiding and burning the coastline of the Union could tie up a lot of troops and divert a lot of troops from the attacks in Tennessee.
5) Also, Union has partial blockade, so much worse logistics and finances.
On ASB type TL, many things are ASB if the POD is a few days before the event you want to change, but easily doable if the POD is moved a decade or two back. I wanted to do a TL where the German had twice as many U-boats started the war, and I simply could have posted in the ASB section. But instead, I went back 14 years to get a POD that did the same thing, and settled for a much better trained U-boat fleet with better bases. Look below for the evolution of thought.
https://www.alternatehistory.com/discussion/showthread.php?t=225249
The TL is in my signature.
So I would suggest you think about what you want to happen early in the war for the CSA to win, the back into the POD. For example, maybe you want the CSA to do well in Tennessee, then think about what would have to happen for that to be true. So lets say it would be 100,000 more soldiers for the CSA, so then you ask, what would it take for the CSA to have that many more soldiers. Or maybe you want Britain to intervene in 1861, so you then need to decide what it would take to make the UK want to intervene. You might need a plan to eliminate slavery in the CSA constitution, then you have to work out what the POD is.
There are few things that are truly ASB, if you want to put the work into the TL. Now with the ACW, it is going to be hard to have a POD in early 1861 that causes the CSA to win by late 1862. But if you go back 5 or 10 years, you can probably find what you want. Also, you don't have to strengthen the CSA, you can weaken the USA.
And finally, sometimes a few small POD are easier to handle than one large POD. I had trouble coming to a situation where Germany could have 90 submarines in 1914, so I had a single POD and butterflies. Different leaders early on, means U-boat designs are 1-2 years ahead of OTL. I built lightly fortified ports in Dar Es Salaam and Douala. Then the most important change was better leaders and men, in my ATL, many of the commanders have 5-8 years U-boat experience, not 1-2 years. You might want to look at some option like this for your TL.