Thank’s for your ideas.
The Binci accordina reed plates look fine, I received a photo. They are quite small.
The “wind chest” should be kept as small as possible, to economise on breath.
The individual reed chambers, we also think in keeping these small, we had a look at the plastic Hohner Student 32 tone chambers, but we still have a lot of thinking to do about this point.
Mabye we’ll start a test with a cheap cut up Hohner plastic melodica. And keep the accordina reeds for the 2nd trial.