I fixed the embrasures now entirely. The holes are the same distance apart, only there where it makes sense (no + or T section holes, because pawns can't be behind those anyway, except the flat side of the T, which has a hole).
I also took the time to make proper appearances for all three of the vanilla types (smooth, bricks, planks) and for neo, which is the orassan hexagon pattern, which I also made for Diana a while back.
You have to change
<graphicData>
<texPath>Things/Building/Linked/Embrasure</texPath>
<graphicClass>Graphic_Appearances</graphicClass>
</graphicData>
Inside "Linked" make a folder "Embrasure" and inside that folder put the four PNGs, similar to a graphic_stackcount or graphic_multi. The appearances are saved on the stuff, so nothing further is necessary.

Also a new menu icon, this time without the brick pattern, because the vanilla wall UI icon has no pattern either (there are some in the assets, but they are never used)
The actual vanilla brick pattern has some errors (see my bug report
here) - this is already fixed for these assets.
Here are the files: