The default range for all maps in UO is still 1024 units (I think that's the same as old CoD). Tried changing the cvar (cg_hudCompassMaxRange) for the compass when connected to a UO server, but it is flagged as read-only.

Only a few maps use a different value in UO. Look in the GSC files for those two maps for:

game["compass_range"] = 13000;

Here's the maps that I've found that override whatever the default is:

mp_arnhem - 2816
mp_berlin - 2816
mp_foy - 6124
mp_italy - 13000
mp_kharkov - 6124
mp_kursk - 13000
mp_rhinevalley - 12500

Notice that Ponyri does not have a default value! Which means that Ponyri is using a compass range of 1024 units, even for BAS/CTF/DOM.

Anyone know what would have to be done server-side to override or add new values to the game's GSC files? Or is it better to do a server-side mod that puts an upper limit on the compass size?

Or maybe someone knows where to change the default compass size setting?

So the current rules for compass range are:

1. defaults to 1024
2. Unless the map is one of the above
3. Gets reset to 1024 if the game type is BEL, DM, HQ, RE, SD, or TDM

That means on a map like Italy, all of the new types (BAS, CTF, DOM) will use a compass range of 13000 units, while any of the old game types end up with a compass range of 1024 units.