Does the oven need a circulation fan?
A low profile or horizontal format oven of small volume will probably not need a fan. The distance from the elements to the roof is small and the heat radiates well enough to heat the interior pretty evenly. As the volume increases, or if the oven is a vertical format with a larger distance from bottom to top, a fan should be considered. A fan from a convection kitchen oven would be an excellent choice, as would a fan from a downdraft cooktop. The fan from the cooktop would probably move too much volume and would require a choke to limit the volume somewhat.
