I leave my Savoy hanging where it gets to 115F and humidity gets a little "robust," at certain times, too.
OK so far, but the problems mentioned here are a concern.
Blackbird publishes what temps and conditions their guitars can accommodate, so you would think they would stand up to the claims.
You can read them here (click on the relevant FAQs)...
https://www.blackbirdguitar.com/pages/faqs
Llamarebel, I found your comments on the El Capitan interesting. It's one of the composite guitars I would like to try but haven't had the opportunity.
As a steel string, my Savoy has some unique qualities, but was no match for my CA GX. Works great as a nylon. Would be curious to know your thoughts if you were to give nylon strings a test.