Alright so I purchased a back extension about over a year ago. I looked at them both. The 45 degree back extension and the flat one...I bought the flat one and not the 45 degree one. Is there a difference between the two, is the 45degree back extension better? The flat one you can change heights of it so if you set it either lower or higher (the pins) you can feel your back doing most of the work and if you set it on the higher ones you can feel your glutes/hamstring work more. What do you guys thinks? And what do you have?