You guys are killing me with tuning talk. I like it and hope to dig in one of these days. Here are a couple of thoughts.
The harmonica tuning videos on the Hohner website are filled with conceptual information directly related to tuning melodicas. They recommend pinging the reeds several times after bending for gap adjustment to enable the reed to settle into its final position. Then adjust and ping again if needed.
In the PR video for the Hohner Museum and/or the history of Hohner (found on the corporate website or museum website or both), they show a few seconds of a reed plate being tuned. Tuning only took a couple second per reed. I was not sure if the reed plate was bare or mounted in a harp or melodica, but it was open to the air to enable metal removal, somehow air was being blown through the reed to make it sound.
I thought they must either be blowing air from the back side or maybe shooting a stream of compressed air from the front directly at the reed. This would save having to adjust the tuning blind and then having to reassemble to test your work. One of these days I will shoot compressed air at a reed when I have my air compressor operating.