It sounds like everything is fine. Good for you for experimenting. If you want him under the light more, yes lower the wattage and he will stay there because it takes longer for him to hit his optimum temp if he gets to it at all. Hes in the stack cuz he found the temp he likes, the point I was trying to make is that you are giving him a choice of temps and let him decide. opposed to deciding the ig only get 100-110 because the keeper thinks thats enough.
I'll stop now so I dont dig deeper

jf