When I first learned to hand roll it was a marginal affair. If the wind was blowing from the west. If the stars aligned. And if I remembered all of my move then maybe, just maybe, the roll would work. I used momentum and a lot of arm muscle to force the kayak to roll up. Over time I learned to slow down. I learned to reach up with my body and then to lean back and use my spine to start the kayak rolling. But every practice roll I was doing started tucked forward and ended on the back deck in one continuous motion. This was great for the pool but ineffective as a combat roll. Last year I started practicing using a hand roll as a recovery technique when failing at other rolls. This trained me to be able to start in the wrong position. To set myself up underwater and then roll up. This has become very useful when practicing, and failing, my forward finishing hand rolls. I now can attempt a forward finishing hand roll and if it fails I revert to a layback hand roll and recover that way.
I suggest that everyone should practice all their rolls so they are not relying on the kayaks momentum to complete them. Last weekend I spent a considerable time practicing chest sculling without a paddle. This allowed me to develop forward finishing hand roll recoveries from a position that it is fairly easy to setup and with the kayak static in an inverted position.