How comfortable are you taking a HEX editor to your game files? In the post that @CasualClick linked, there is this one that shows how to change them to your liking. I tried this and found it to work for me. And you can tweak things as you see fit.
It appears that this specific file hasn’t been touched in any of the recent SU’s or WU’s, as I have not had to re-do my changes for quite a while.
https://forums.flightsimulator.com/t/make-taxi-arrows-smaller/281714/15?u=bigcow74