Steal away!!
My perches are 6 inches off the floor but my cage is 14 inches high. I believe the T-8 is 12" if I'm not mistake. You could certainly give it a go and I'd suggest mounting yours a bit further back so you can still reach in and around without always having to pull the perches out.
My real tree branch perches are not straight and dip a bit so they are only 3-4 inches off the floor in some areas.
One thing I want/need to do is make the bamboo a little more rough. The vines spin easily on it and if my guy is not sharing the other 2 branches he sometimes grips and then the vines spin, he goes upside down and will fall if he is not gripping tightly.
After a few spills he seems to realize that branch is a bit more tricky.
I'm considering moving our Royal from her glass tank into this cage and moving up to and 18" or 24" high cage. Not to give her (BP) a bigger cage, but to increase the ceiling for the boa.
There is NO DOUBT that if a boa has a chance to climb, perch and feel evenly supported, that it will do so.
Every feeding session with the exception of 2 have been arial assaults.
You will enjoy your snake experience 10X more when you give them a cage that challenges them as nature would.
That said if you have a large number of snakes, this can become quite a task.