Seems I can't get the ClientRate above 15000 or 20000 which is LAN/T1 according to the game, even when modifying the LAN/T1 entry in SwatGUIState.ini, for which I did with all three SwatGUIState.ini files to be certain. Modifying ConfiguredInternetSpeed=15000 under [Engine.Player] in Swat4X.ini doesn't work either, the game will forcefully revert the change, and will refuse to play if the file is set to read-only.
In Swat4X.ini, under [IpDrv.TcpNetDriver], is MaxInternetClientRate=7000, maybe this is what the other hosters were running their ClientRate at.
I'm using the dedicated server batch file, inorder to use it however, you must "host server" in the game itself, and pick the desired options for the server. The dedicated server reads from this; if you try to modify the SwatGUIState.ini yourself with an editor (not from in-game), it will be overwritten whenever you need to change something on the server while in-game.
My settings currently for Swat4XDedicatedServer.ini is:
LAN tickrate is modified since I connect to the server through LAN.
Changed MaxConnPerIPPerMinute from 5 to 25 since tickrate of 100 is 5 times the value of 20, 20 being the default for non-local multiplayer; I have no idea if this matters.
LogMaxConnPerIPPerMin is enabled to see if changing MaxConnPerIPPerMinute matters or not.
Server is ready to go now.
Before joining: Go to Settings, Game Controls, then select LAN/T1 for the connection speed.
Then edit this file in the SWAT 4 folder: SEF/System/Swat4X.ini
Add bCapFramerate=False under [Engine.LevelInfo], then save the file.