Michael,
Put me in the hit them for fun category. As noted, roll outs are important, but can't really be determined. The best way to do that is to take a digital level out to courses you have designed previously or are playing. If a cross slope kicks the ball too far, measure it and make a mental note. Balls really don't roll out anywhere in dirt.
Short version, professional gca's should kind of know what basic slopes work in the situation you describe beforehand! Although, there was a recent thread -What happens when a kickplate doesn't kick - which describes how design intentions can get messed up in wet conditions, inappropriate (for that feature) maintenance, etc.
When I designed Colbert Hills, we wanted to play a dirt round with the crew so I went down to a local golf shop, looking for used and cheap balls for about 2 dozen guys (some who don't play) to blast around. I picked up all the used balls, and then saw some $1 balls and went back to get those. Then I saw some more, etc., and ended up buying about 6 dozen. Went to pay and the guy behind the counter asks, "Wow, just how bad a golfer are you?"