Functionality

This mod replaces the vanilla Bannerlord party size modifiers with a configurable system allowing them to be tweaked or even disabled at will. The following vanilla party limit modifiers can be freely adjusted:

• Base party size
• Clan tier size factor (separately adjustable for clan leader and clan members, and major/minor clans)
• Quartermaster (Stewardship skill) factor
• Kingdom leader bonus
• Caravan party size factor
• Villager party size
  

There are also several non-vanilla, Warband-inspired options that can be substituted or added to the vanilla functionality at will!

• Renown scaling factor (separately adjustable for clan leader and clan members)
• Owned castles bonus
• Social attribute bonus
  

These values apply the same to the player, their companions' parties, and all other NPC lords. 

Configuration

Uses MBOptionScreen to make all options adjustable via an in-game configuration screen. This mod must be after MBOptionScreen in your load order!

Perk Fixes

In addition, in vanilla Bannerlord, almost all party size affecting perks are unimplemented (With the sole exception of Ultimate Leader, which is merely implemented incorrectly, at least according to its own description) - this mod implements those perks, as follows:

• Bow - Merry Men: increases personal party size by 3.
• Throwing - Skirmishers: increases personal party size by 5.
• Riding - Squires: increases the current party's party size by 2.
• Riding - Conroi: increases the current party's party size by 4.
• Steward - Bannerlord: increases personal party size by 2 per owned fief (town/castle).
• Steward - Man At Arms: increases personal party size by 5 per owned fief (town/castle).
• Steward - Swords As Tribute: increases personal party size by 10 per vassal, if kingdom leader.
• Leadership - Ultimate Leader: increases personal party size by 1 per point of Leadership above 250. (This perk appears twice in the vanilla tree, but the mod will only grant the bonus once.)
• Trade - Mercenary Trader: This perk remains unimplemented, as it does not even have a defined object in the game's code to make calls to.
  

Compatibility

Can be freely enabled or disabled on an existing save.

Uses a Harmony patch to prefix CalculateMobilePartyMemberSizeLimit in DefaultPartySizeLimitModel, meaning compatibility with other mods shouldn't be an issue. If combined with mods that postfix that method (eg Bannerlord Tweaks), the effect will simply be cumulative.

Troubleshooting

If experiencing crashes on startup without an error message, try unblocking the .dll files (right click - properties - unblock at bottom, if it appears.) And try using one of the fixed launcher mods!

I've been having similar issues to this thread on my personal machine:
https://forums.taleworlds.com/index.php?threads/game-wont-start.396670/page-18
So consulting the solutions in there may help. 

If crashing persist even after disabling the mod, removing the folder entirely may help, especially if combined with other solutions.