Another thing you may want to consider is the type and size of hides you have. It sounds like you've built some custom hides which is fine, but really you want to have at least two that are exactly the same and size appropriate. One on the warm side and one on the cool side. Your BP will choose security over warmth and may just be finding the "best" hide where he feels the most secure. This could be another reason why he isn't eating for you, along with the temperature fluctuations and humidity issues.
Also a big red flag is the amount of handling you're doing. I know you feel like he "likes" being out and being handled, but snakes don't "like" handling, they just come to tolerate it. You could never touch him and it would have no ill effects on him. You should not be handling him until he's eating consistently for you.
Lastly, and I apologize if I missed it, what I assume you're referring to going out 3 times is your UTH, I'm not sure what brand you're using but this is a little suspect to me. Can you tell us brand you're using, what you have it set to, etc etc? I've got zoomed UTHs running right now that have been going for years with no issue, so it surprises me that you're going through yours so quickly.