Always ask modding questions in this section: https://forums.taleworlds.com/index.php?forums/modding-q-a.538/.
As I mentioned in another thread of yours, make sure to use ModSys for transparent edits of the module. Messing with compiled text files is very troublesome. If you learn some basics of modding, you will easily find a solution to your problem.
There is a file module_skills.py and also there are some scripts in module_scripts.py which modify skills. These are what you are looking for, but remember that you will need time to find what you need. Make sure to follow some startup tutorials to ensure a smooth workflow.
Actually there are lots of modding resources out here, you need to dig deeper. The thread for modder newbies: https://forums.taleworlds.com/index...post-new-at-modding-warband-read-here.448322/. The section for them (make sure to refer to its subforum for guides): https://forums.taleworlds.com/index.php?forums/the-forge-mod-development.64/.
There should be a snippet in the source code governing the Leadership skill, find it and adjust to your preferences.
Here are released mods for WFaS: https://forums.taleworlds.com/index.php?forums/with-fire-and-sword.254/. When it comes to modding the source code, adding new skills is rather difficult but it is actually easy to mod the existing ones. Go to Modding section and then to The Forge to kickstart your M&B engine modding adventure and learn some basics.
It can easily be done through modding the game. I advise you not to play unmodded WFaS because it is too grindy and you will waste your time and get frustrated before even conquering a single settlement. Instead, I recommend you to try an enhancement mod out or mod the game to meaningfully boost your standing. Seriously, playing vanilla is a waste of time.