I have a window air conditioner but when it is really humid here in NW penn there isn't much I can do. House will get around 75percent in the summer with a few dry days in the mid 50 percent to mid 60 percent. I made a few bows last winter when humidity was in 30 percent range and in the summer they became noodles
(they were fast this winter) I have built 4 this summer and cast is down a bit but at least the bows don't lose 8 lbs of draw weight due to humitidy changes cause they were tillered when humidity was high. If I get the feeling the bow is just too wet I put in in truck w windows up for 3 or 4 days.
I just finished tillering a couple of hickory bows and despite the humidity one only took 1 inch of set the other less but I havent' shot it much yet.
Heat treating seems to help as well if done early before bow takes set and after tiller is done just before final tiller.
Greg