i agree with him - i can't code at all so i was forced to go this route to build some projects for my last position. i invested a lot of time in the specs to start with and as the contractor and i got more comfortable with what 'success looked like' it got a lot easier and soon he was suggesting improvements or implementing some features on the fly (you gotta earn that kind of trust). the key for me was to make sure each set of tasks was distinct and i could actually test something that works each week - ended up with 4-5 solid iterations before we finished and the weekly turnaround let me get a lot of good feedback from others.