Now, to address the "splitting of carriers" issue.
At the start of the game, I posted Ent and Lex around Timor. They saw a bit of action. From there I posted them near Cocos Island to protect that key island from what I figured was imminent invasion. (If you don't think Cocos is a key island, then you and I won't see eye-to-eye on this.) That patrol ended up lasting months. As Steve began to move into the Bay of Bengal, my carriers moved west. They did make a move north (joined by Hornet) from the vicintiy of Diego Garcia to engage, but Indomitable took a sub torp, so I pulled them back. Since then, they've been upgrading in the yards at Bombay, which they've just finished. As it turns out, these carriers saw little action, but they did watch over Cocos, Diego and Socatra, each of which I consider very important. Steve guessed or worried that my carriers might be present, so I think this played a factor in his decisions not to move on these bases.
Sara and York remained near the West Coast. At first, I intended to use them as security for the Aleutians, but when it became clear that Steve was moving there with overwhelming force, and then taking some of the key Canadian bases, I held them in reserve. Primarily, I wanted their fighters to serve as a strategic reserve for the West Coast industrail targets. Indeed, I ultimately stripped the fighters and sent them to LA and San Diego, where they remained for several weeks. The big threat I faced there was Steve using LBA to hit northwest USA bases while his carriers hit SoCal. This was a major problem that I countered with only marginal success.
So my carriers ended up on opposite sides of the maps, though for good reasons IMO. Consolidating them would take weeks, and I'm pretty sure that Steve would have suspected and detected such a move, so that he would have consolidated his own.
Now we've reached a new point in the game. Sara and York are in SoPac, probably enroute to Melbourne for upgrades and yard time. That gives me a better opportunity to consolidate somewhere down the line, though I would be shocked if Steve keeps his carriers separate. We'll see.
All this to say: I'm satisfied that splitting my carriers was helpful to the Allied cause.
independent of the question if we agree on certain bases/areas to be important, the problem I see is that two or even three USN carriers can't do anything other than keeping away a non carrier supported IJN move. Ok, so you might have two carriers preventing the Japanese to take a single base in the Indian Ocean, but only preventing them doing so without carrier support. Now I am sure if your opponent would see that base as as important as you, wouldn't he just bring his carriers and invade the place while you could not do anything about it with two carriers? If he brings all his carriers you also can't do anything about it (well, you could try and usually end up losing to the IJN 1:1) so we are again at the point where all it achieved was to prevent an IJN invasion that isn't supported by carriers. On the other side, your opponent had carrier superiority on the whole map, while it was enough for him to run around carrier groups not even carrying 300 aircraft and this has lead to a lot of panic on the Allied side IMO. It even allows him to bomb Pearl Harbour in mid 42, even if it isn't more than a prestige attack.
Many of your enemy's operations would have been slowed down or wouldn't have been carried out the way they were if your opponent would have just known you would have 4 or 5 USN plus 2 RN CV in one basket, well being able to to take on everything not of the size of KB. And if he still would have pressed on the way he did, you would have had ample of chances to wreck havoc while not going in if you knew KB would be nearby.
There are of course tactical reasons why one would split his carriers at times but strategically seen, the best thing for the Japanese that can happen in 42 is the Allied player splitting his carriers into two or three divisions that are spread out all over the map because that asures the Japanese to have total superiority wherever a couple of his carriers show up, something I wouldn't dare if I knew I could face 400+ Allied carrier based ac any moment. But yeah, you achieved what seems to be a big thing for you, you prevented the invasion of Cocos Island, that might have never even be planned by the Japanese, which is something I do not know, for giving the Japanese total superiority on the whole map for 6 months (which they shouldn't have if they split KB).
It's absolutely ok to have different oppinions on this topic IMO and I hope you don't mind my comments, it's just that I think you put too much panic into your grand strategy and have too much of a view of the uber abilities the Japanese (independent of the skill of IJ High Command), which they actually don't have.