I understand there are a number of ways of reflowing individual SMT boards. I've seen small temperature profile ovens, hotplates, skillets, airbaths, and hot air guns used. I'm trying to determine which method is most appropriate for low-volume (<100 per year) commercial production of SMT PCBs.

I've observed something being done by another company, though at smaller volumes. Their reflow method was to preheat the board with an [air bath](http://www.zeph.com/airbathseries.htm), then spot-heat the board with an air gun to complete the reflow. They claimed a long and effectively problem-free history with this method.

Is this a viable method of SMT reflow for the volumes I'm talking about? Are there particular flaws or problems to watch out for?