Overview
A quick guide on how to enable larger map sizes
How to enable
In order to enable experimental map sizes you HAVE to go into your game files and editing your settings in your local steam folder.
Pathfinding
Open File explorer>This PC>Local Disc (C:)>Program Files (x86)>Steam>userdata>(Your Steam ID)>1066780>Local
Open the settings text with notepad
Hit CTRL+F and type in experimental
Replace False to true
File>Save
You should be able to launch the game and start a free game and see the megalomaniac setting as well as the 1:5 setting.