Hi Simchaleh,
To answer your other question, all the keys on all my vintage Hohners are the same width. When I compared the width of the keys on my vintage Hohners with the width of the keys on my new Yamaha, there was about half an inch difference between the two melodicas over a two octave range. The Yamaha’s 25 keys were in total about half an inch shorter in width than 25 keys on the Hohners. I can’t even tell the difference when playing. Lowboy