Same RH for me too. Canadian Rockies. Like Denver North basically. But the big 9 gallon humidifier I got works great. I've got it on low fan speed and middle humidity setting and I have a solid, so far consistent 50%. Could probably go quite a bit higher if I wanted too, like jungle/rainforest humidity territory. But I don't want to go above 50% because of mold. And the big tanks mean I don't have to refill multiple times per day. Might get away with refilling every two days.
I'm watching my plants now to see if I notice any differences. I do actually but I'm not sure I got a real handle on this at all. I also reduced my temp from like 80F to 70F to get this in the VPD green zone. Now when I walk in the tent it feels cool and just a little humid. Feels comfortable. If I was a plant, I'd say it feels stress free!!!