Use them the same way as in lower trophy count but be more selective and use rage or lightning plus heroes.
Healer won't work that high.
Personally I am trying to replace the healer so i don't want to use it. Also, one of the reasons i am posting this is because my leader can farm with barb and arch at 2500-2700. However he doesn't have time to explain to me.
Look up one piece the clan about 19000 trophies and look at the top player he uses arch and barb to farm has only spent $20 on the game.