I see a difference if I keep the glass off for a few hours, but not if I'm just opening and closing it. my T8's pretty much stay at 60% humidity all the time.
a proportional thermostat will keep the temperature at 90 degrees all the time maybe a half degree variance.
the T8 is completely flat, but flexwatt is only 0.01 inches thick (for comparison a sheet of printer paper is 0.004 inches thick so flexwatt is about the thickness of 2 sheets of paper) as long as the flexwatt is regulated by a thermostat it won't get hot enough to cause any problems.
this is how it is sectored to the bottom:
and once again read this, I guarantee it will answer most of your questions: http://ball-pythons.net/forums/showt...With-Pictures!