[mingustoo]

Michael,
Your trip and meeting with the factory bosses was of course very important. Not just as a means for checking out their capability, but as a means of developing a personal relationship with the owners.
I work for a trading company in Taiwan and can tell you that impressing upon them your dedication to quality and commitment to following your design tolerances is of the utmost importance. In China it doesn't matter what is being made, work WILL be farmed out and if you or the subcontractors ( but mostly you) are not on top of it, cheating, fudging, substituting of cheaper parts WILL take place.
Moreover, personally inspecting the facilities brings prestige to the factory as it shows to them how important they are in your business plan.
Just remember, with most businesses in China, only after the contract is signed does the real negotiating begin.