no probs eh8811y
bouncy chu silica gel isn't a thirsty hippo. maple is a very stable wood and any sort of cracking is most probably cuz of poor construction than humidity change.
eh8811y, how did your dad look inside his classical? Mould doesn't grow on wood that much. Pure wood doesn't promote mould growth so you shouldn't worry about that, it's more of MDF boards that mould likes. Maybe 5-6 years would result in guaranteed mould growth. I think few people can tell you if hollow bodies will grow mould because it's hard to look inside. My dad's classical is over 30 years old and I'm still playing it. It's been left in some damp storeroom in melaka for years and mould growth haven't been observed.