Use AE and load your mod (if you follow the diretions and copy the my_mod stuff, then it uses the same info as the base game without hindering online play) and go to where you want to edit it. There is a 'Min Squad Size' (The size the squad is made at) and a 'Max Squad Size' (Determines how many other people can be added to the squad)
Ye i know about those lines and what they do but I think I may have found what I am looking for GameData["requirement_ext"] = Reference([[ebpextensions\requirement_ext.lua]]) GameData["requirement_ext"]["requirements"]["required_1"] = Reference([[requirements\required_cap.lua]]) GameData["requirement_ext"]["requirements"]["required_1"]["max_cap"] = 1.00000 would this be setting the limit to 1 as I have seen this line in the ork squiggoth, the farseer and the space marine land raider...
Oh ye i forgot the build for it
Squad Build Limits
Don't edit the files directly, as it doesn't work too well. Use Attribute Editor.