The very last mission is challenging. My refined strategy is to press directly west from the starting point once the base has been established (smelter & a few scavengers to continue building Judas' and warlords/commandants with healing ability) with a Judas and capture as you go, killing reapers and saving anything you can capture. I send vortex singularity units to the smelter because they often kill my own units.
Once you press West, you attack the civilian factories and have a few captured units hang out there to kill any constructors that try to rebuild them. Soon all constructors will be destroyed, making it impossible for the enemy to replenish any destroyed factories.
Once the constructor population withers, I send in a strike team that destroys the four light infantry factories directly North-North-East of the starting point. This is usually done with a first person Gorilla that I capture, and the strike is done by masterfully toggling between the different weapons systems by pressing Tab and hitting one building with missiles while punching another. That will severely reduce the amount of pressure the main area experiences.
From that point on, if the Gorilla survives, I'll continue north and start destroying bases until he is killed.
Then I switch to the southeast front and press north in a clockwise fashion, capturing units as they are built from factories and using them to attack the factories while I press on in my Judas.
It takes a while and a lot of micromanaging using the Pause button, but I believe this strategy is one of the most effective.