Here's mine: squad speed 500 -550

?-1 and ?-2: standard setup
?-3: left to right, 2-1-2. Place a fast helper squad at the left and your slowest at the top right and pray for the helper to go the middle path.
(also good for farming since the middle path will be still closed when you finish the map)
?-4: standard setup. I got lucky I guess