Although I only have used the Planet Waves system for maybe a week or so, I adhere to your views. In addition I feel bad when installing the Planet Waves pouche and observing how much friction there is between the pouch and the soundhole. It does not take too much reasoning to realise that this practise eventually will mark the edge of the soundhole and possibly also the edge of the fretboard, if playing the guitar every day. My guitar is not the most expensive in the world, but it is brand new and I treat it like a precious jewel Therefore it just does not feel right to force the pouch into the soundhole. It also messes up the tuningsouldier wrote:I've always found them cumbersome to insert and remove from the sound hole of a classical since they are more designed for steel string guitars which have larger sound holes. So I opt to keep them at the head stock. If your case has space by the heal of the neck, they can go there as well. I use my own home made sponge solution for the sound hole. When I play my guitar, I want the process of opening the case and removing the guitar to be quick, painless and smooth.
The main thing you need to worry about with these humidipaks is that they have liquid inside. Be extra careful when handling them to ensure you don't accidently puncture the packet as there have been numerous reports of them leaking inside the guitar and causing permanent damage (you can easily find these reviews online). Since they are cumbersome to insert and remove from the sound hole and there is that possible risk of puncturing the bag when doing this, I only use them at the head stock or at the heal of the neck.
As far as their reusability is concerned... I have a set of 3 packs that are almost a year old and they are still running strong. I have 6 packets in total that I basically cycle between so that they never run dry. While one set is being used, the other set is being recharged *See picture below*. I'm glad I only have one guitar now, so I only need 2 sets.
I believe I also want place the Planes Waves pouches at the headstock and find another solution for the soundhole.
Could I ask what kind of device you have come up with for use in the soundhole?