I make no claims to being an expert, but some builders like to aim for torque, others aim for high rpm power, and some try to hit somewhere in the middle. A short duration camshaft in a small cubic inch engine with a fairly large valve and port cross section will still like to turn some rpm.
Most cam companies give generic recommendations. You either have to know somebody there or get mediocre results.
Re read my cam test article and read between the lines.
A certain big name cam company had a horrible suggestion and I had similar recommendations from some people's beloved experts.
The way I look at what is needed has to do with how big a cylinder the valve has to feed and what rpm range is going to be needed.
You need to know the head flow numbers all the way up and past the lift range you are considering to make the best choice. Hope I haven't confused you even more.
Keith