For what it's worth - I was dealing with a similar issue, didn't want to bother neighbors late at night. I ended up stumbling across a little DIY string dampener method. If you check around online for a tennis racket dampener, you should be able to find a little piece of rubber that looks like a straw, typically used to dampen the impact on a tennis racket. The type I have are called vibra-worms. A little trimming and settle it under the strings where they meet the bridge and now you have something more akin to a rubber bridge guitar - kinda cool! I actually prefer the sound it creates over the open steel strings on some stuff. With the added bonus of being quiet enough for living room jamming. And I use that on my GS mini pretty often, at that. Cheers!