The Settings depend on your Biomes. There are no Magic "I win" settings with CHC.
The CHC is Highly Dependend on the actual BiomeHeight.
That means, it doesnt depend on the Setting in your BiomeConfig. Rather it depends on how high the Terrain Generates. (One Leads to the Other, obviously. Higher BiomeHeight -> Higher Surface)
So, basically almost every Setting in your BiomeConfig will change the Result of the CHC settings.
So you need some Testing/Tweaking to get it Right.
Now to CHC itself, so you Understand it Correctly.
Basically, the SurfaceHeight of the Biome determines a "Chance to Spawn Blocks".
How it works Internally I have no Idea. But Basically CHC can tweak this chance in Layers.
You can use either small Values to just Tweak Terrain. or Large Values to Cut away large Parts of Terrain.
For Example: If you have a Ground at around 64 blocks with some Hills going to 70.
You can tweak CHC like this:
CustomHeightControl: 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, -25.0, -50.0, 50.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0
Which should give you some Overhanging Cliffs in the Hills.
Each value represents 7 Blocks, so, to Change the Blocks around 64-70 I tweaked the 9th, 10th and 11th value. -25, and -50 will remove some Blocks, while +50 will add some.
The Further you are going away from your Actuall surface, the Higher the Values need to be to get an Effect.
For Example, these are the Values I used for a Part of my SkyLands:
CustomHeightControl: -50000.0, -50000.0, -45000.0, -40000.0, -35000.0, -30000.0, -27500.0, -25000.0, -22500.0, -20000.0, -17500.0, -15000.0, -7500.0, -3000.0, -950.0, 175.0, -25.0, 0.0, 0.0, -25.0, 0.0, 0.0, -25.0, 0.0, 0.0, -25.0, 0.0, 0.0, -25.0, 0.0, 0.0, 0.0, 0.0
To prevent Blocks spawning near Bedrock I have to use Massive Negative Values, because the Actual Surface of the Terrain is above 120 Blocks.
Another Thing to note is, that while the Values affect roughly 7 Blocks in Height, they will also start Affecting larger areas if the Value is Larger. For example, If I were to lower a Value between (or Increase if you think it Mathematicly) I wont get a chunk of Terrain Below the Islands with a Depth of 7 Blocks. It would be only 1-3 Blocks in depth.
So, to get your UnderWater Caves you would start with a Value of -2500 at the Height you want. and then Tweak yourself into the Direction you want.
As for the Entrances, see my Previous Posting. I´m sure I told you one or two ways to get the Entrances.
As for the Swampland:
It appears that the Swampland Spawns then, but the Biomeheight is below the Sea Level, or something. You need to revisit your Land Biomes and check that you use Correct values.