List of changes:
The Lobby and offline Squad editor menus now allow selection of more than 6 soldiers
The spawn area has been increased to allow extra troops to spawn
If you can think of any improvements, let me know.
UPDATE - I've fixed an issue that was causing the mod not to work in some cases.
Installation
1. Copy the extracted folder to this location:
Steam\steamapps\common\XCOM 2\XComGame\Mods
2. Enable 'MPLargerSquads' in the mod launcher
3. Play