As Yann mentioned Ive experienced issues with young helis that were constantly in the direct flow from the humidifier. Wistuba also mentions in his recommendations that helis do not like excessive misting.
Now I use to mist mine a couple times a day with good results... just don't over do it IMHO, give them a chance to dry out some, especially before bed
Like most variables there is a point of diminishing returns
Nice temps btw, fwiw we have practically identical setups, but yours is a little nicer
While not absolutely required, I have bagged Wistuba helis for a couple weeks while they recover from their journey and acclimate somewhat. However, the last bunch I got in I simply put in a lower airflow/higher humidity region of my rack and they did just as well.
Just watch for early signs of desiccation for a couple weeks, it can happen quickly
speaking from experience but ymmv