If you want battle sizes anywhere from 150 to 1000 you may want to try this:

IMPORTANT NOTE
If you have 5 years old rig or newer you should be able to run 250 - 350 battle on HD settings so in that case only use Battlesizer.

INSTURCTIONS BATTLE Sizes 150-350
1. Install Battlesizer 1.5 (separately documented instructions)
2. In-game go to Camp, Pre-Battle Orders Settings and set the same battle size number as you've set in Battlesizer


INSTURCTIONS BATTLES 350-1000
1. Install Battlesizer 1.5 (see separately documented instructions)
2. Install Quantity Plugin (see instructions below)
3. In-game go to Camp, Pre-Battle Orders Settings and set the same battle size number as you've set in Battlesizer



Quantity Plugin Info and Installation

This plugin reduces flora variation, flora population and uses flora with less demanding models.

Add this plugin to any BannerPage version from 2.0 onwards. Unpack archive and put in the BannerPage folder and when asked - overwrite. 
If you want to revert to original BannerPage version just use the same logic and apply QUALITY Plugin.
IMPORTANT - Please note that it takes 10 - 20 random scenes loadups before vegetations balances out (during that process you may see weird scenes)

