We can get up high. Our most recent blog post has pictures of our robot and practice/prototype robot fully extended.
http://3847.blogspot.com/
We had the idea of blocking full court shooters pretty early on. The horns at the top of the lift get to 83.75".
The robot is as stable as the robot I worked on in 2011 for Logomotion. It would tip if we accelerated full throttle (6 CIMS) at full height but not if a we were just pushed in the bumper zone. We also have bumpers plus 20 more pounds of weight to add to the frame.