So another thought.
Am not sure yet, as the melodica is new to me and the techniques described above are new to me, but I think I am favoring smaller melodicas (26-key and 27-key) over the larger ones, at least for executing the above techniques. These smaller melodicas are simply easier and lighter to move around. And if I select the right melodica for the song (soprano or alto), the range is normally sufficient. This early opinion could change, but right now that is what I am thinking. I have a couple of light Piano 32s that are also relatively easy to manipulate.
If the above wha wha and vibrator techniques are not important in the song, and I am looking for a slightly brighter sound, there is nothing like pulling out the relatively larger and heavier Hohner 36-key Piano.
The above playing techniques take some getting use to and require some practice before you can really maximize the modulation. I am still finding them tricky to execute while I am playing, but they add such expressiveness (at least to the bluesy kind of music I play), that I plan on working at them to perfect the techniques. I only discovered these techniques 2 or 3 weeks ago, so I have a way to go to fully integrate them into my playing.
I will try to post a short recording within a week of what these playing techniques sound like.