Less,
If I wash with water and soap, I dry with towels and use the leaf blower to just blow out the water hiding in the seams and crevices. I don't use it dry the entire car. I tried a couple of times, but it didn't really work for me and I didn't want to risk gouging the paint. Also, when I wash with water, I use the flood method where I allow the water to flow freely over the paint so most of the water sheets off, leaving minimal amounts to dry.
I honestly don't think using the blower with ONR would be beneficial. If anything, you are drying out the ONR that has dirt trapped in it. This would leave dirt without any kind of moisture barrier between the paint and the drying towel. I spread the ONR with my sheepskin mitt onto a panel and then immediately dry it off with two towels. The first one to get most of the moisture off and then the second to completely dry it off.