This map SUCKS for 4 splitting, but it makes the cloud farm better. :3 Unfortunately it is highly RNG dependent on IF your actually spawn on all the islands to build, otherwise you can't 4 split.
Only real points of note for the build is that spiders are completely optional, BUT it does make the ogre wave much easier!
Blue = Mortars; Yellow = SAM Unit
Note #5 is where the ogres spawn, just for reference.