Setup gamemode details in severtravel URL

Hello,

we have build a muilti-map/multi-gamemode game in which the players can chose the combination of game mode and map to their like.
Now the game mode can be changed through building a travel URL before server travel so we can use the same map for different game mode.
But we still need to change some of the variables in the game mode like: MaxPlayerTeam & WinScore.
I read about using options like “?MaxPlayerTeam=####” to setup the game option, but it’s not doing any effects for the game now.
Should we do something like “?bMaxPlayerTeam=####” or “?UMaxPlayerTeam=####”?

Thanks for all the help!