Ask HN: How do tight technical specs effect the off-shore dev experience?

I have a background as a developer and product manager. I'm looking to build the middleware and backend for my startup project and considering hiring an offshore dev for the iOS work. I've heard both horror and success stories and I'm hoping, so long as there isn't outright fraud, that tight technical specs and eyes on the code base will mitigate a lot of the risk. I'm hoping to get feedback from other technical folks in a similar situation.