Testing Multiplayer Game for Dedicated Server

Hi togheter

Im trying around with UE4 to make a mmofps withe the “World Browser” tool know i have added some landscapes in different levels to stream between the maps for dedicatet server mode, know i have two questions. How can i edit two landscapes they are saved in different levels for a smooth transition, without to put they together in the same level to edit both at the same time? And the second question is how can i find out with how many players(clients) i can run my maps on dedicated server mode? At the moment the engine crash because the world browser is active when i test with multiple clients with the “play” button, but i know this will be fixed with 4.3. But how can i find out how many npc’s i can put in my map and with how many active clients at the sime time can i play the map without lagging crashing ect. Whitout to make a private LAN-Party?

Thank you