Agree with Richard. Slow temperature changes do not push my alarm buttons.
My preference for humidity is more lenient than ideal--with 40%--60% range being acceptable.
And I really think "slow change" being the key.
In 1995, our youngest son, a Sophomore in college mentioned he would like a guitar to learn on. I found a good used Sigma, no case, made by Martin and he got it Christmas of '95. He graduated college in '98 brought all his "gatherings" home and his Sigma was in a cloth bag with be a draw string. My wife nor I knew nothing about storing a guitar so we put it on a shelf in an outdoor storage building. In 2019, 20 years later, when I was hooked on learning to play and had a DV52, my wife casually says, "Ryan's guitar is in the storage building." I knew a little bit about heat, humidity, and guitars then. That is 20 years of winters, summers, rains, and storms with the inside of the building matching the humidity and temperatures of those 20 years.
We walk down, unlock the building, and she reaches upon a shelf and hands me the bagged guitar.
I took it in the house, loosened the draw strings, and not one crack, or split, or warp, or twist. Tuners all worked fine - tuned it and played, "What a Friend We Have in Jesus." Next day, I put new strings on it and had my guitar teacher lower the action. Son has it at his house, now.
Maybe $300-400 guitar. If I did that to good guitar, I betcha it would have been ruined.
, at first joint and if that isn't good for what you want to do, trim off a little more.
