The issue you've found was a bug in my code, it should be fixed in the next version (not 100% sure yet, because it only occurs with very rare configuration settings). Thank you for that.

At first I was very surprised that you made 16x work. Actually comparing your Toric picture with my Continental one, the biomes in Toric seem to be smaller, and that's probably why overall it takes less RAM. For a given size, Continental is more compact, and so fills more space. Making "larger" maps was one of my motivations to create this shape initially.

If you don't mind, I'll keep the max size in this mod at 16x since I believe it won't work in most cases and will avoid people wasting time in trying impossible sizes. Since the game crashes at about ~3.5 GB, you could probably go much higher with Toric though.

Found something else. Not sure why this is happening but:
Forest_map.lua
["huge"] = 450,
["giant"] = 640,
Checked this just after patching with a multiplier of 10.4. So shouldn't this be (much) higher?
Now it starts to make sense why I was able to make these worlds I think.

Ah, I see. This is a big bug, it was reading the configuration value selected in the regular "Giant Size" mod, if you have it, so probably the default value. Not the 10.4x you selected.

I've pushed a fix. You've found 2 bugs in 2 days ;)

okay. I now see why I wouldn't be able to use this mod (only in rare cases). Only if this game was 64 bit ;) But I can't go higher than 3x with the mods I'm using or it crashes with the lack of memory.
When using a dedicated server I can go a little bit higher compared to client-only.

Yea, using 64 bit would have been better but I guess DST team didn't think the memory consumption would be an important factor. I didn't try it with other mods but I think even 2-3 times is OK for me.
What I fear the most would be the game starting well during the first days but increasing memory consumption as you play and interact with the world. So it's probably safer to keep a little margin if we don't want the world to become unplayable at 100 days.

boom finally after 5 years, 10.4x with megarandom done. I'll post screenshots and I might try 16x a bit later, since i still have like 15gb of RAM free, but yeah check a new discussion for screenshots and some other info. (revealing map at the time of writing this)