I'm trying to make a formation of 1-40 mobs move towards a specific location. My idea is using a unit as formation leader and calculate the end targets for each mob, call my path-finding algorithm and call movement proc so all mobs move to their spots. Note all mobs have the same speed and formation is scalable.

so the problems/questions are:
1.Is this a good approach or is it outdated?
2.How can I prevent the units from breaking their formation? Because by implementing the above all I saw was the units breaking formation to move through obstacles and reunite at the target point. (I don't mind breaking the formation 1-3 tiles to avoid a tree, but what happened was half my regiment moved from one path and the other took a different path around a mountain... is there a way to tie the mobs to formation leader?)

I'm trying to make a battle system similar to total war, I've done some stuff to optimize my code so the game does not crash in the middle of the battle. It works fine for 80 mobs moving simultaneously.

Also what would be the maximum mobs that byond can handle?