concentrate on life+nature+dark
8 level 3 life towers
2 level 3 trickery towers. With this build and some smart placement and earning interest, you can reach first level ice frogs with 50k gold (trade in ur last 2 lumber with essence) and more than 350+ life.
With those trickery towers, u essentially have 16 life towers
once ice frog stage begins, build another trickery tower to handle spawning of 4 pure-dark towers (since their dmg is 97k).. now u have a total of 8 pure-dark towers and 20k gold to spare
with this build, i can hit more than 330 ice frogs