A brief walkthrough for cloaking your way to victory over the final boss:
Core principle:
Cloaking has a static cooldown. Using it to it's best advantage means only ever using it for as long as possible - the sooner it ends, the sooner you can use it again.
Step 0: (preperation)
If you have stealth weapons, trash them before this fight. They will do the opposite of helping. Okay, that's not actually strictly true - it can help a bit on the first form. But it's better to replace them with something useful.
Make sure you have a halfway decent engine and someone manning it - It's important that the cloak brings you up to, or at least close to, 100% evasion, since we won't be counting on it's lockdown ability so much as it's evasion boost.
Step 2: (Stage 1)
Switch power to max for fighting the first form. You want to disable the enemy weapons for as long as possible while you disable them, so you have the chance to kill all but one of the crew, and the cloak stops standard enemy weapons from charging.
Step 3: (Stage 2)
Reduce power consumption on the cloak to 2. This means you'll need a bit tighter timing, but this will last through the entirety (or at least bulk) of the drone attack. Leave it at three if you're not comfortable with your timing and you can do the following.
Step 4: (Stage 2)
Cloak as soon as the drones appear on screen. As soon as the drone attack ends, /fire a weapon/. You want your cloak to end ASAP, and firing weapons will knock chunks off it. The faster it goes down, the faster it starts reloading.
Step 5: (Stage 3)
Finally, reduce your cloak power to 1 for this fight. The attacks all hit at roughly the same time, so you don't need a cloak that's longer - you need a cloak that recharges as fast as possible.
Step 6: (Stage 3)
Again, cloak after the plasma enters your screen, and fire your weapons as soon as the last bolt misses. This should give you plenty of time to recharge before the next blast.
Finally... VICTORY! Good job! You win!