Quetscher, I think the air chamber of plastic would have solved a lot of moisture issues. Remember Victoria is an accordion manufacture so they were using basic accordion making theory and not taking to account the woodwind moisture issues. My Vibrandoneon does the same thing in regards to the lower octave when played hard (leakage). As for the wood material used in the making of the Vibrandoneon there are a couple of issues that come up, 1st, the wood material must be a workable, too hard of a wood may not machine as well as softwood. Also there are a lot of woods that are not really good for humans to be around “allergies” so this needs to be taken into consideration when a product is going to be sold and what possible issues the material chosen may cause in the future to the end user. I agree with you that the wood should at least be sealed with a good moisture repellent. If you have a lot of allergies a “food safe sealer” like what they use on wooden bowls or wooden spoons can be used. Normally you can use any finish, including varnish, lacquer, shellac, and boiled linseed oil as long as you allow for the proper curing time.