You have a 150 degree basking spot for a boa? That's ridiculous...and yeah ...dead space. Why not cool that area down and allow the snake more room to use? What's the point of having a huge cage and then making it so all that space can't be used? 100 degrees ambient causes brain damage. 111 causes death. 150 is just overkill if your goal is to kill your pets.
I wouldn't use dirt for a large snake. They tend to make a lot of mud when they come out after a soak. Maybe the reason some of your monitor buddies don't like snake people is that the snake people are more in tune and you guys just get frustrated for not hearing what you want to hear or being told you are wrong all the time? Be right for once and maybe we will grow on you

Personally, the only other monitor person I know of that doesn't like me is that dances with savs whackjob and it's all quite mutual. A lot of my friends keep monitors. Please refrain from projecting your feelings on such a huge group. They can speak for themselves. You can only speak for you...and that dances with savs whackjob guy. I'll give you that since you two are probably joined at the hip anyway.
