If I add that large of a sweetener at bottling will it over carbonate and become a bomb?
Yes.
If so what recommendations are there for keeping a desirable sweetness?
As Tress said, you can use Potassium Sorbate to stop the yeast from reproducing, and then sweeten. If you bottle it will be still (uncarbonated). If you have keg technology you can force carbonate at this point. That is my plan for my next batch of cider.
Another option that I've read about, but not tried, is to sweeten to taste, bottle, and then pasteurize. You wait a week after bottling, then open one. If it isn't quite carbonated enough, you wait a day or two and open another. Keep doing this until you've reached desired carbonation, then you pasteurize. Basically you heat the bottles in a water bath on the stove until they reach a temperature that will ensure nothing in there ever grows again, but not so hot as to significantly change the flavor. You'd have to google up the details. It looks like a hassle to me.