Thanks...that helped

After breaking down my roll, I discovered three things:
1) Yup, too much pressure on my spine :/
2) Lazy hand placement, especially by not pushing down hard enough, is THE source of error for me. Correcting this helped immensely.
3) Sideways roll > QM roll

(just messing with you, Adam ^_^)
But yeah, the sideways roll feels a lot nicer for me. Lifting off is a little awkward, but I'm sure I can fix that.
Nonetheless, my roll is far from perfect. I'll need to practice a lot more before I even think about going on concrete, and that's not counting the fact that I have yet to roll with my left shoulder :-(
Damn you ambidextrous people!!! "shakes fist"