Awesome! Glad to hear it was useful. What material did you end up using?
Regarding the rubber tube I’ve been using: the main issue I’m having with it is that the moisture in the tube runs down the smooth internal sides and collects much more easily than in the corrugated tubes. I’m begging to wonder if the reason for the corrugation is less about kink prevention and more about this. I can get through about 1 tune before I have to blow the tube out due to it getting clogged with moisture… it was never that bad with the regular tubes. My suspicion is that the corrugation slows and spreads the moisture. The upside is that the rubber tube may prevent most of the moisture from getting in to the actual melodica (the way I play, it pools at a low point in the tube before the instrument), so I’m not sure which I prefer in the long-term.
I’ve thought about lining the inside of the rubber tube with techflex… if it was the right diameter maybe it could be pulled through and would act to slow the moisture in the same way. But of course it might impede airflow.
And I sometimes think about building a little “spit trap” just before the melodica that could contain the moisture for a longer period.