Best use of miniatures?
When miniatures are used well, they are almost undetectable. The Republic studio was blessed with two of the best model-builders in Hollywood: Howard and Theodore Lydecker. The brothers built their miniatures relatively large (1/12 scale) and filmed them outdoors. Many climaxes for Republic serials depended on the spectacular destruction of a Lydecker miniature.
Some of their best work is in the dogfight sequences of "Flying Tigers," where very few scenes used real planes. The wires were painted sky blue. Many Air Corps officers were fooled - that's how good the model work was.
Compare the "Flying Tigers" dogfights to those in "God is My Co-pilot," where the miniatures were not as well-built or well-staged (and the corny dialogue between Dennis Morgan and his Japanese opponent did not help). It's said that Robert Scott, the real-life pilot portrayed by Morgan, was embarrassed by those scenes.