What is needed to defeat the base: (The base being the one where the outer most defenses are mortar and Hellfire turrets with the 4 bunkers in a symmetrical fashion, kinda like a diamond shape)
Level 9 Elite Hellfires
Level 8 or 9 Elite Warhawks
Gatling Trucks (The higher level the better) (4 is the preferred number)
1) Use EWH to destroy the vulnerable towers that will threaten the EHF when they go to attack.
2) Use Gats as a shield to take the sniper fire from the South East Bunker while EHF''s take out the bunker.
3) Next, use EHF's to target their towers while remaining out of range of the Plasma and Barrage towers. The splash damage should destroy all nearby flak and gat units around the barrage and plasma turrets. (If you fail to destroy all AA units, you will have to find a way to destroy them, use whatever you think is suitable to take them out without loses)
4) Use EWH to destroy the turrets that are now exposed to air attacks.
5) Nearly there now, Now this part is the tricky part. Spawn ONLY 1 EWH and send it around to the OPPOSITE side of the base, making sure that all the flak and gats are *aiming* at it. (Since they are on stand ground they wont move to attack it, but will remain Locked on unless another air unit gets too close.) Now, spawn the other EWH and go through the gap in their defenses that has been created and begin attacking the CC.
If done correctly, the flaks will not turn around to attack and in about 2 minutes the CC will fall. If done correctly, the only losses you would had suffered would had been from your gates which can be micro healed in less 10 minutes.
Notes: There are many other ways and variation to my own strategy to defeat the bases, but ive found this suites me well as it offers a simple strategy to quickly and swiftly defeat the base.
I hope this helps and good hunting commanders