In the first menu of the DMS launcher press the button "DARTHMOD NORMAL SIZE (MP SETTING)".
All players must use this same setting to be compatible with each other.
Join Multiplayer Matches with online compatible players
Reverting to Vanilla Multiplayer:
By version 3.45 of the mod the procedure is automated perfectly.
You simply press the button DISABLE TO PLAY VANILLA and start the game.
This way your Preferences will be deleted (to make the game fully Vanilla) so you have to re-set them in the graphics sections of the game.
To re-enable the mod just press DARTHMOD DEFAULT 1,5X or DARTHMOD DEFAULT NORMAL SIZE.