Alright played around with some of the files and finally created a somewhat working Version for me.
https://www.dropbox.com/s/c1qcglqhmqc37qc/Twonky%20Fix.zip?dl=0
For everyone with the same Problems that I'm having just put it into your mod folder and load it. I deleted the ocean and sand biome and added limestone and copper to grasslands since that is the only biome that can generate so this way you can play around with everything in the game. The map just looks pretty ugly since there is only grasslands and weird River/Mountains.