Although some are loathe to admit otherwise, this mod absolutely kills performance on ultra and even large unit size compared to vanilla. I'm trying a Wurzag campaign on ultra unit size (big mistake) and some battles, even 20 vs 20s, start REALLY chugging bad. It gets so bad that it affects my ability to pan the camera effectively during a battle. I have this:

RTX 2080 super
i7 8700
16 GB RAM

Using the skaven benchmark test in the graphics settings, I notice I get 20 average FPS lower with the mod on vs the mod off on the ultra settings. Hell I even get higher FPS in vanilla with the mod on large unit size vs vanilla on ultra unit size.

This is with NO other mods active. I even have shadows reduced to high and AA only on FXAA.

Here are my settings for those curious, ultra unit size: https://imgur.com/tVciiuU
Skaven benchmark GRIMHAMMER, ULTRA UNIT SIZE: https://imgur.com/Ja7rFIf
Skaven benchmark GRIMHAMMER, LARGE UNIT SIZE: https://imgur.com/QHcLXt1
Skaven benchmark VANILLA, ULTRA UNIT SIZE: https://imgur.com/M0aL80a

As you can see, the vanilla performance is FAR better, even compared to SFO large unit size. Do not be fooled by the somewhat ok avg FPS you see above, I promise you the FPS is in the constant 20s during simple 20 v 20 wurzag open field battles, along with some annoying stuttering when I pan the camera to include every unit