I was watching a video by Stephen Wright, showing how to do the back deck roll. I noticed something that made me realize just how simple it is to do the back deck roll. In some of the examples, he stops at 90 degrees, before he does a snap. If you look at the roll, at that 90 degrees and after, it looks identical to a C to C roll after you hit the 90 degree mark. This showed me that the back deck roll is simply an alternate method to put yourself at 90 degrees before snapping your hips. Once I realized that, I went from struggling to easily hitting my back deck roll.