I find it funny how garrisoning your army barely does anything for additional replenishment, there isn't even a difference between a shared and an owned province when you garrison.
Default land regeneration is 4 while both ways of garrisoning only provide an additional 2 >.<
I know you can improve replenishment with technologies etc, so I tried not to go too crazy.
I included a small, medium, large, and extreme improvement to replenishment when garrisoned.
So I hope you find something to your liking.