Help creating biomes!

[Milordo]

Hello. 

Just a quick ask for help because I'm pretty sure I'm going to the asylum for this.

I'm experimenting with the modworldgenmain for creating different worlds. At this point I'm a bit knowledgeable and learned a lot, but for some devilish reason, I can't in any way create this scenario -->

What I want is to create a world (possibly caves), exactly as you see in the picture. Various biomes, sometimes linked with pitrooms, and at one point the connection is separated by a small piece of land that you NEED to traverse with spelunker's bridge kits. That's all. The problems I've come upon are: sometimes the little piece of land doesn't appear and the biomes are connected, and mossttt of the time the "upper land", for some reason, bend on itself, like it's trying to connect itself with the mainland, as showed here in the picture -->

And I don't want this!!! I've tried anything. ForceDisconnect, ForceDisconnectrooms, Roadpoison, not_mainland, everything. Even using static layouts. Everytime I can't make the land not bend on itself OR in the few times I've done it right.... the land is just a bit further for bridges to connect.

Help please :c How it could be done.

[Milordo]

UPDATE: I discovered something while experimenting more. I thought that separating the two long chunks of land and placing a small island in between would cause the top portion of the land to curve towards the center of the world, but I was wrong.

For clarity of what I'm talking about -->

After doing a lot of testing, the top portion would curve anyway, sometimes or always depending on the settings, even though there wasn't the small island in the center separating the two chunks!!!
So this means there's something in Klei biomes logic and levels, that if a large, long strip of lands forms, it will cause the land to curve towards the center (OR maybe I'm missing something in my code, but I'm only using the usual AddTasks and AddRooms, nothing out of the ordinary). 

Obviously, for what I want, I have to prevent this, but I don't even know where to start... Does anyone have any ideas how to fix it?

Edited February 22 by Milordo