Okay, Health does not directly affect accuracy, what it affects is the condition of the object in question. I believe the game has preset values at which it considers a weapon to be damaged. It should be using percentages, but it isn't. Essentially, if you set the health of a weapon BELOW it's default value, the game will treat it as a damaged weapon - it will be less accurate, and may even do less damage (never tested that part). As far as I know, increasing the health beyond the starting level has very little effect, although that may not be true. The most common error modders make is to bring the health of the Gravimetric Torpedo down to the level of the other weapons - which instantly makes it far less accurate than it should be, as it's default health is 70 and most of the others have between 35-50.
As far as I can tell, there's no point going above 80, except for the Borg Primaries.