Edit:
So I've been told that downloading that file and just adding it to that directory didn't work. Don't know why, perhaps during the installation of the mod it adds something to the game.pref file. My mistake, and my apologies if I wasted your time trying this. At least it works on my pc.
I know it's been said that the Advanced Strategic Icons mod is getting worked on to be easily customisable, but here's a temporary simple solution for anyone who wants it. Place this .nxt file:
https://ufile.io/ucr5qs4r
in
C:\ProgramData\FAForever\gamedata
It uses the small versions from the mod of nuke, SMD, TML and TMD. I also took the ACU icon and increased it from about 12x12 pixels to 16x16. It made it blurry due to pixels doing their thing, so I touched it up just now by hand in Gimp to make it crisp again.
@Zlo @Tagada