I don't know yet how extensive the corrosion really is; just that it has been found in a few small areas. Only an A&P looking through the wing can determine if ittruely is not a problem, or if there is serious damage.
Knowing what you know about the condition of this airplane, would you feel comfrotable flying acrobatic manuevers up to +6 and -3 g's in this particular 1978 Aerobat? If you do, and no more corrosion damage is found, then it is a good find.
What exactly will Corrosion X do for me? Will it stop corrosion that has already started? What would the approximate cost be to apply throughout the airframe?
Corrosion X stops the corrosion, inihibits further corrosion, and seeps into the seams of the skin. You're entirely correct - only an A&P can determine if it is a problem. But as far as felling comfortable doing aerobatics in it?
Yep.